example/ivy/android/app/src/main/java/org/golang/ivy/MainActivity.java - mobile - Git at Google

 /*
  * Copyright 2015 The Go Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style
  * license that can be found in the LICENSE file.
  */

 package org.golang.ivy;

 import android.content.Intent;
 import android.content.pm.ApplicationInfo;
 import android.net.Uri;
 import android.os.AsyncTask;
 import android.os.Build;
 import android.os.Bundle;
 import android.text.TextUtils;
 import android.util.Log;
 import android.util.Pair;
 import android.view.KeyEvent;
 import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
 import android.webkit.WebView;
 import android.webkit.WebViewClient;
 import android.widget.EditText;
 import android.widget.ImageButton;
 import android.widget.ScrollView;
 import android.widget.Toast;

 import androidx.appcompat.app.AppCompatActivity;

 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;

 // This is in ivy.aar.
 import mobile.Mobile;

 /*
  * Main activity that consists of an edit view to accept the expression
  * and a web view to display output of the expression.
  */
 public class MainActivity extends AppCompatActivity {
     final String DEMO_SCRIPT = "demo.ivy";  // in assets directory.
     final String DEBUG_TAG = "Ivy";
     final String PROMPT = "> ";

     private WebView mWebView;
     private EditText mEditText;
     private ScrollView mScroller;

     private BufferedReader mDemo;
     private ImageButton mOKButton;  // enabled only in demo mode.

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         mScroller = (ScrollView) findViewById(R.id.scroller);
         mWebView = (WebView) findViewById(R.id.webView);
         mEditText = (EditText) findViewById(R.id.editText);
         mOKButton = (ImageButton) findViewById(R.id.imageButton);
         mOKButton.setVisibility(View.GONE);

         if (savedInstanceState != null) {
             mWebView.restoreState(savedInstanceState);
         } else {
             clear();
         }
         configureWebView(mWebView);

         mEditText.requestFocus();
         mEditText.setOnKeyListener(new View.OnKeyListener() {
             public boolean onKey(View v, int keyCode, KeyEvent event) {
                 if ((event.getAction() == KeyEvent.ACTION_DOWN) && (keyCode == KeyEvent.KEYCODE_ENTER)) {
                     callIvy();
                     return true;
                 }
                 return false;
             }
         });

         mOKButton.setOnClickListener(new View.OnClickListener() {
             public void onClick(View v) {
                 callIvy();
             }
         });

         /* For webview debugging - visit chrome://inspect/#devices */
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
             if (0 != (getApplicationInfo().flags & ApplicationInfo.FLAG_DEBUGGABLE))
             { WebView.setWebContentsDebuggingEnabled(true); }
         }
     }

     @Override
     protected void onSaveInstanceState(Bundle outState) {
         mWebView.saveState(outState);
         super.onSaveInstanceState(outState);
     }

     public void onRestoreInstanceState(Bundle savedInstanceState) {
         super.onRestoreInstanceState(savedInstanceState);
         mWebView.restoreState(savedInstanceState);
     }

     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         MenuInflater inflater = getMenuInflater();
         inflater.inflate(R.menu.menu_main, menu);
         return true;
     }

     private long mLastPress = 0;
     @Override
     public void onBackPressed() {
         // TODO: store and restore the state across app restarts.
         long currentTime = System.currentTimeMillis();
         if(currentTime - mLastPress > 6000){
             Toast.makeText(getBaseContext(), "Press back again to exit.\nAll app state will be lost upon exit.", Toast.LENGTH_LONG).show();
             mLastPress = currentTime;
         }else{
             super.onBackPressed();
         }
     }

     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
         int id = item.getItemId();
         switch (id) {
             case R.id.action_about:
                 startActivity(new Intent(this, AboutIvy.class));
                 return true;
             case R.id.action_help:
                 startActivity(new Intent(this, Help.class));
                 return true;
             case R.id.action_clear:
                 clear();
                 return true;
             case R.id.action_demo:
                 loadDemo();
                 return true;
             default:
                 return super.onOptionsItemSelected(item);
         }
     }

     private void clear() {
         // As described in https://code.google.com/p/android/issues/detail?id=18726
         // clearing the contents of the webview doesn't shrink the webview size in some
         // old versions of Android. (e.g. Moto X running 4.4.4). I tried various techniques
         // suggested in the Internet, but nothing worked except creating a new webview.
         WebView newView = new WebView(this);
         newView.setLayoutParams(mWebView.getLayoutParams());
         newView.setId(R.id.webView);

         configureWebView(newView);

         mScroller.removeView(mWebView);
         mWebView.destroy();

         mWebView = newView;
         mWebView.loadUrl("file:///android_asset/tape.html");
         mWebView.setBackgroundColor(getResources().getColor(R.color.body));
         mScroller.addView(mWebView);

         mEditText.setText("");
         Mobile.reset();
         unloadDemo();
     }

     void configureWebView(WebView webView) {
         // We enable javascript, but disallow any url loading.
         webView.getSettings().setJavaScriptEnabled(true);
         webView.setWebViewClient(new WebViewClient() {
             // Disallow arbitrary contents loaded into our own webview.
             public boolean shouldOverrideUrlLoading(WebView view, String url) {
                 view.getContext().startActivity(
                         new Intent(Intent.ACTION_VIEW, Uri.parse(url)));
                 return true;
             }
         });
         webView.setFocusable(false);
         webView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
             @Override
             public void onLayoutChange(View v, int left, int top, int right, int bottom,
                                        int oldLeft, int oldTop, int oldRight, int oldBottom) {
                 // It's possible that the layout is not complete.
                 // In that case we will get all zero values for the positions. Ignore this case.
                 if (left == 0 && top == 0 && right == 0 && bottom == 0) {
                     return;
                 }
                 scrollToBottom();
             }
         });
     }

     private String escapeHtmlTags(final String s) {
         // Leaves entities (&-prefixed) alone unlike TextUtils.htmlEncode
         // (https://github.com/aosp-mirror/platform_frameworks_base/blob/d59921149bb5948ffbcb9a9e832e9ac1538e05a0/core/java/android/text/TextUtils.java#L1361).
         // Ivy mobile.Eval result may include encoding starting with &.

         StringBuilder sb = new StringBuilder();
         char c;
         for (int i = 0; i < s.length(); i++) {
             c = s.charAt(i);
             switch (c) {
                 case '<':
                     sb.append("&lt;"); //$NON-NLS-1$
                     break;
                 case '>':
                     sb.append("&gt;"); //$NON-NLS-1$
                     break;
                 case '"':
                     sb.append("&quot;"); //$NON-NLS-1$
                     break;
                 case '\'':
                     //http://www.w3.org/TR/xhtml1
                     // The named character reference &apos; (the apostrophe, U+0027) was introduced in
                     // XML 1.0 but does not appear in HTML. Authors should therefore use &#39; instead
                     // of &apos; to work as expected in HTML 4 user agents.
                     sb.append("&#39;"); //$NON-NLS-1$
                     break;
                 default:
                     sb.append(c);
             }
         }
         return sb.toString();
     }

     private void appendShowText(final String s, final String tag) {
         mWebView.loadUrl("javascript:appendDiv('" + TextUtils.htmlEncode(s).replaceAll("(\r\n|\n)", "<br />") + "', '" + tag + "')");
         mWebView.setBackgroundColor(getResources().getColor(R.color.body));
     }

     private void appendShowPreformattedText(final String s, final String tag) {
         mWebView.loadUrl("javascript:appendDiv('" + escapeHtmlTags(s).replaceAll("\r?\n", "<br/>") + "', '" + tag + "')");
         mWebView.setBackgroundColor(getResources().getColor(R.color.body));
     }

     private void callIvy() {
         String s = mEditText.getText().toString().trim();
         if (s != null && !s.isEmpty()) {
             appendShowText(PROMPT + s, "expr");
         }
         if (mDemo != null && s.trim().equals("quit")) {
             unloadDemo();
             s = " ";  // this will clear the text box.
         }
         new IvyCallTask().execute(s);  // where call to Ivy backend occurs.
     }

     private synchronized void loadDemo() {
         try {
             if (mDemo == null) {
                 mDemo = new BufferedReader(new InputStreamReader(getAssets().open(DEMO_SCRIPT), "UTF-8"));
             }
             mOKButton.setVisibility(View.VISIBLE);
             new IvyCallTask().execute("");
         } catch (IOException e) {
             Toast.makeText(this, "Failed to load Demo script.\nContact the app author.", Toast.LENGTH_SHORT);
         }
     }

     private synchronized void unloadDemo() {
         if (mDemo == null) { return; }
         try {
             mDemo.close();
         } catch (IOException e) {
             Log.d(DEBUG_TAG, e.toString());
         }
         mDemo = null;
         mOKButton.setVisibility(View.GONE);
     }

     private synchronized String readDemo() {
         if (mDemo == null) { return null; }
         try {
             return mDemo.readLine();
         } catch (IOException e) {
             unloadDemo();
         }
         return null;
     }

     private void scrollToBottom() {
         mScroller.post(new Runnable() {
             public void run() {
                 mScroller.smoothScrollTo(0, mWebView.getBottom());
             }
         });
     }

     // AsyncTask that evaluates the expression (string), and returns the strings
     // to display in the web view and the edit view respectively.
     private class IvyCallTask extends AsyncTask<String, Void, Pair<String, String> > {
         private String ivyEval(final String expr) {
             try {
                 // mobile.Mobile was generated using
                 // gomobile bind -javapkg=org.golang.ivy robpike.io/ivy/mobile
                 return Mobile.eval(expr);  // Gobind-generated method.
             } catch (Exception e) {
                 return "error: "+e.getMessage();
             }
         }

         // doInBackground checks the demo script (if the passed-in param is empty),
         // or returns the ivy evaluation result.
         @Override
         protected Pair<String, String> doInBackground(String ...param) {
             final String expr = param[0];
             // TODO: cancel, timeout
             if (expr == null || expr.isEmpty()) {
                 return checkDemo();
             }
             return Pair.create(ivyEval(expr), "");
         }

         // checkDemo reads the demo script and returns the comment, and the next expression.
         protected Pair<String, String> checkDemo() {
             String showText = null;
             while (true) {
                 String s = readDemo();
                 if (s == null) {
                     break;
                 }
                 if (s.startsWith("# ")) {
                     return Pair.create(s, null);
                 }
                 return Pair.create(null, s);
             }
             return null;
         }

         @Override
         protected void onPostExecute(final Pair<String, String> result) {
             if (result == null || (result.first == null && result.second == null)) {
                 return;
             }
             runOnUiThread(new Runnable() {
                 @Override
                 public void run() {
                     String showText = result.first;
                     if (showText != null) {
                         final String tag = (showText.startsWith("#")) ? "comment" : "result";
                         appendShowPreformattedText(showText, tag);
                     }
                     String editText = result.second;
                     if (editText != null) {
                         mEditText.setText(editText);
                     }
                 }
             });
         }
     }
 }
	/*
	* Copyright 2015 The Go Authors. All rights reserved.
	* Use of this source code is governed by a BSD-style
	* license that can be found in the LICENSE file.
	*/

	package org.golang.ivy;

	import android.content.Intent;
	import android.content.pm.ApplicationInfo;
	import android.net.Uri;
	import android.os.AsyncTask;
	import android.os.Build;
	import android.os.Bundle;
	import android.text.TextUtils;
	import android.util.Log;
	import android.util.Pair;
	import android.view.KeyEvent;
	import android.view.Menu;
	import android.view.MenuInflater;
	import android.view.MenuItem;
	import android.view.View;
	import android.webkit.WebView;
	import android.webkit.WebViewClient;
	import android.widget.EditText;
	import android.widget.ImageButton;
	import android.widget.ScrollView;
	import android.widget.Toast;

	import androidx.appcompat.app.AppCompatActivity;

	import java.io.BufferedReader;
	import java.io.IOException;
	import java.io.InputStreamReader;

	// This is in ivy.aar.
	import mobile.Mobile;

	/*
	* Main activity that consists of an edit view to accept the expression
	* and a web view to display output of the expression.
	*/
	public class MainActivity extends AppCompatActivity {
	final String DEMO_SCRIPT = "demo.ivy"; // in assets directory.
	final String DEBUG_TAG = "Ivy";
	final String PROMPT = "> ";

	private WebView mWebView;
	private EditText mEditText;
	private ScrollView mScroller;

	private BufferedReader mDemo;
	private ImageButton mOKButton; // enabled only in demo mode.

	@Override
	protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main);

	mScroller = (ScrollView) findViewById(R.id.scroller);
	mWebView = (WebView) findViewById(R.id.webView);
	mEditText = (EditText) findViewById(R.id.editText);
	mOKButton = (ImageButton) findViewById(R.id.imageButton);
	mOKButton.setVisibility(View.GONE);

	if (savedInstanceState != null) {
	mWebView.restoreState(savedInstanceState);
	} else {
	clear();
	}
	configureWebView(mWebView);

	mEditText.requestFocus();
	mEditText.setOnKeyListener(new View.OnKeyListener() {
	public boolean onKey(View v, int keyCode, KeyEvent event) {
	if ((event.getAction() == KeyEvent.ACTION_DOWN) && (keyCode == KeyEvent.KEYCODE_ENTER)) {
	callIvy();
	return true;
	}
	return false;
	}
	});

	mOKButton.setOnClickListener(new View.OnClickListener() {
	public void onClick(View v) {
	callIvy();
	}
	});

	/* For webview debugging - visit chrome://inspect/#devices */
	if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
	if (0 != (getApplicationInfo().flags & ApplicationInfo.FLAG_DEBUGGABLE))
	{ WebView.setWebContentsDebuggingEnabled(true); }
	}
	}

	@Override
	protected void onSaveInstanceState(Bundle outState) {
	mWebView.saveState(outState);
	super.onSaveInstanceState(outState);
	}

	public void onRestoreInstanceState(Bundle savedInstanceState) {
	super.onRestoreInstanceState(savedInstanceState);
	mWebView.restoreState(savedInstanceState);
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
	MenuInflater inflater = getMenuInflater();
	inflater.inflate(R.menu.menu_main, menu);
	return true;
	}

	private long mLastPress = 0;
	@Override
	public void onBackPressed() {
	// TODO: store and restore the state across app restarts.
	long currentTime = System.currentTimeMillis();
	if(currentTime - mLastPress > 6000){
	Toast.makeText(getBaseContext(), "Press back again to exit.\nAll app state will be lost upon exit.", Toast.LENGTH_LONG).show();
	mLastPress = currentTime;
	}else{
	super.onBackPressed();
	}
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
	int id = item.getItemId();
	switch (id) {
	case R.id.action_about:
	startActivity(new Intent(this, AboutIvy.class));
	return true;
	case R.id.action_help:
	startActivity(new Intent(this, Help.class));
	return true;
	case R.id.action_clear:
	clear();
	return true;
	case R.id.action_demo:
	loadDemo();
	return true;
	default:
	return super.onOptionsItemSelected(item);
	}
	}

	private void clear() {
	// As described in https://code.google.com/p/android/issues/detail?id=18726
	// clearing the contents of the webview doesn't shrink the webview size in some
	// old versions of Android. (e.g. Moto X running 4.4.4). I tried various techniques
	// suggested in the Internet, but nothing worked except creating a new webview.
	WebView newView = new WebView(this);
	newView.setLayoutParams(mWebView.getLayoutParams());
	newView.setId(R.id.webView);

	configureWebView(newView);

	mScroller.removeView(mWebView);
	mWebView.destroy();

	mWebView = newView;
	mWebView.loadUrl("file:///android_asset/tape.html");
	mWebView.setBackgroundColor(getResources().getColor(R.color.body));
	mScroller.addView(mWebView);

	mEditText.setText("");
	Mobile.reset();
	unloadDemo();
	}

	void configureWebView(WebView webView) {
	// We enable javascript, but disallow any url loading.
	webView.getSettings().setJavaScriptEnabled(true);
	webView.setWebViewClient(new WebViewClient() {
	// Disallow arbitrary contents loaded into our own webview.
	public boolean shouldOverrideUrlLoading(WebView view, String url) {
	view.getContext().startActivity(
	new Intent(Intent.ACTION_VIEW, Uri.parse(url)));
	return true;
	}
	});
	webView.setFocusable(false);
	webView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
	@Override
	public void onLayoutChange(View v, int left, int top, int right, int bottom,
	int oldLeft, int oldTop, int oldRight, int oldBottom) {
	// It's possible that the layout is not complete.
	// In that case we will get all zero values for the positions. Ignore this case.
	if (left == 0 && top == 0 && right == 0 && bottom == 0) {
	return;
	}
	scrollToBottom();
	}
	});
	}

	private String escapeHtmlTags(final String s) {
	// Leaves entities (&-prefixed) alone unlike TextUtils.htmlEncode
	// (https://github.com/aosp-mirror/platform_frameworks_base/blob/d59921149bb5948ffbcb9a9e832e9ac1538e05a0/core/java/android/text/TextUtils.java#L1361).
	// Ivy mobile.Eval result may include encoding starting with &.

	StringBuilder sb = new StringBuilder();
	char c;
	for (int i = 0; i < s.length(); i++) {
	c = s.charAt(i);
	switch (c) {
	case '<':
	sb.append("<"); //$NON-NLS-1$
	break;
	case '>':
	sb.append(">"); //$NON-NLS-1$
	break;
	case '"':
	sb.append("""); //$NON-NLS-1$
	break;
	case '\'':
	//http://www.w3.org/TR/xhtml1
	// The named character reference ' (the apostrophe, U+0027) was introduced in
	// XML 1.0 but does not appear in HTML. Authors should therefore use ' instead
	// of ' to work as expected in HTML 4 user agents.
	sb.append("'"); //$NON-NLS-1$
	break;
	default:
	sb.append(c);
	}
	}
	return sb.toString();
	}

	private void appendShowText(final String s, final String tag) {
	mWebView.loadUrl("javascript:appendDiv('" + TextUtils.htmlEncode(s).replaceAll("(\r\n\|\n)", "<br />") + "', '" + tag + "')");
	mWebView.setBackgroundColor(getResources().getColor(R.color.body));
	}

	private void appendShowPreformattedText(final String s, final String tag) {
	mWebView.loadUrl("javascript:appendDiv('" + escapeHtmlTags(s).replaceAll("\r?\n", "<br/>") + "', '" + tag + "')");
	mWebView.setBackgroundColor(getResources().getColor(R.color.body));
	}

	private void callIvy() {
	String s = mEditText.getText().toString().trim();
	if (s != null && !s.isEmpty()) {
	appendShowText(PROMPT + s, "expr");
	}
	if (mDemo != null && s.trim().equals("quit")) {
	unloadDemo();
	s = " "; // this will clear the text box.
	}
	new IvyCallTask().execute(s); // where call to Ivy backend occurs.
	}

	private synchronized void loadDemo() {
	try {
	if (mDemo == null) {
	mDemo = new BufferedReader(new InputStreamReader(getAssets().open(DEMO_SCRIPT), "UTF-8"));
	}
	mOKButton.setVisibility(View.VISIBLE);
	new IvyCallTask().execute("");
	} catch (IOException e) {
	Toast.makeText(this, "Failed to load Demo script.\nContact the app author.", Toast.LENGTH_SHORT);
	}
	}

	private synchronized void unloadDemo() {
	if (mDemo == null) { return; }
	try {
	mDemo.close();
	} catch (IOException e) {
	Log.d(DEBUG_TAG, e.toString());
	}
	mDemo = null;
	mOKButton.setVisibility(View.GONE);
	}

	private synchronized String readDemo() {
	if (mDemo == null) { return null; }
	try {
	return mDemo.readLine();
	} catch (IOException e) {
	unloadDemo();
	}
	return null;
	}

	private void scrollToBottom() {
	mScroller.post(new Runnable() {
	public void run() {
	mScroller.smoothScrollTo(0, mWebView.getBottom());
	}
	});
	}

	// AsyncTask that evaluates the expression (string), and returns the strings
	// to display in the web view and the edit view respectively.
	private class IvyCallTask extends AsyncTask<String, Void, Pair<String, String> > {
	private String ivyEval(final String expr) {
	try {
	// mobile.Mobile was generated using
	// gomobile bind -javapkg=org.golang.ivy robpike.io/ivy/mobile
	return Mobile.eval(expr); // Gobind-generated method.
	} catch (Exception e) {
	return "error: "+e.getMessage();
	}
	}

	// doInBackground checks the demo script (if the passed-in param is empty),
	// or returns the ivy evaluation result.
	@Override
	protected Pair<String, String> doInBackground(String ...param) {
	final String expr = param[0];
	// TODO: cancel, timeout
	if (expr == null \|\| expr.isEmpty()) {
	return checkDemo();
	}
	return Pair.create(ivyEval(expr), "");
	}

	// checkDemo reads the demo script and returns the comment, and the next expression.
	protected Pair<String, String> checkDemo() {
	String showText = null;
	while (true) {
	String s = readDemo();
	if (s == null) {
	break;
	}
	if (s.startsWith("# ")) {
	return Pair.create(s, null);
	}
	return Pair.create(null, s);
	}
	return null;
	}

	@Override
	protected void onPostExecute(final Pair<String, String> result) {
	if (result == null \|\| (result.first == null && result.second == null)) {
	return;
	}
	runOnUiThread(new Runnable() {
	@Override
	public void run() {
	String showText = result.first;
	if (showText != null) {
	final String tag = (showText.startsWith("#")) ? "comment" : "result";
	appendShowPreformattedText(showText, tag);
	}
	String editText = result.second;
	if (editText != null) {
	mEditText.setText(editText);
	}
	}
	});
	}
	}
	}