android手势创建及识别

使用一些浏览器或者输入法应用时会有一些手势操作，还可以自定义手势。这些神奇的操作是怎么做的呢？这一篇重点记录手势的识别和创建。这篇的内容使用到的是android.gesture包，具体的例子参考的是Sample中GestureBuilder程序。

1、手势创建

手势创建主要用到GestureOverlayView和GestureLibrary。GestureOverlayView的父类为android.widget.FrameLayout，是手势绘图区。GestureLibrary类主要对手势进行保存、删除等操作的，存放手势的仓库。下面给出创建手势的例子，如下图，可以定义如图手势打开csdn.net

1.1、创建绘图区

 GestureOverlayView overlay = (GestureOverlayView) findViewById(R.id.gestures_overlay);overlay.setGestureStrokeType(GestureOverlayView.GESTURE_STROKE_TYPE_MULTIPLE);  overlay.setFadeOffset(2000);  //多笔画每两次的间隔时间overlay.setGestureColor(Color.CYAN);//画笔颜色overlay.setGestureStrokeWidth(6);//画笔粗细值overlay.addOnGestureListener(new GesturesProcessor());

1.2、监听绘制

 private class GesturesProcessor implements GestureOverlayView.OnGestureListener {public void onGestureStarted(GestureOverlayView overlay, MotionEvent event) {mDoneButton.setEnabled(false);mGesture = null;}public void onGesture(GestureOverlayView overlay, MotionEvent event) {}public void onGestureEnded(GestureOverlayView overlay, MotionEvent event) {mGesture = overlay.getGesture();if (mGesture.getLength() < LENGTH_THRESHOLD) {overlay.clear(false);}mDoneButton.setEnabled(true);}public void onGestureCancelled(GestureOverlayView overlay, MotionEvent event) {}}

1.3、保存手势

 public void addGesture(View v) {if (mGesture != null) {final TextView input = (TextView) findViewById(R.id.gesture_name);final CharSequence name = input.getText();if (name.length() == 0) {input.setError(getString(R.string.error_missing_name));return;}/*** 获取手势库*   private final File mStoreFile = new File(Environment.getExternalStorageDirectory(), "gestures");*   GestureLibrary sStore = GestureLibraries.fromFile(mStoreFile);* */final GestureLibrary store = GestureBuilderActivity.getStore();store.addGesture(name.toString(), mGesture);store.save();setResult(RESULT_OK);final String path = new File(Environment.getExternalStorageDirectory(),"gestures").getAbsolutePath();Toast.makeText(this, getString(R.string.save_success, path), Toast.LENGTH_LONG).show();} else {setResult(RESULT_CANCELED);}finish();}

2、手势识别

手势识别也是经过创建绘图区、监听绘制、比对结果三个过程，这里直接给出代码。

public class GesturePerformedActivity extends Activity {private final File mStoreFile = new File(Environment.getExternalStorageDirectory(), "gestures");// 手势库GestureLibrary mGestureLib;@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.gesture_perform);// 手势画板GestureOverlayView gestures = (GestureOverlayView) findViewById(R.id.gestures_overlay);gestures.setGestureStrokeType(GestureOverlayView.GESTURE_STROKE_TYPE_MULTIPLE);gestures.setFadeOffset(2000); // 多笔画每两次的间隔时间gestures.setGestureColor(Color.CYAN);// 画笔颜色gestures.setGestureStrokeWidth(6);// 画笔粗细值// 手势识别的监听器gestures.addOnGesturePerformedListener(new GestureOverlayView.OnGesturePerformedListener() {@Overridepublic void onGesturePerformed(GestureOverlayView overlay,Gesture gesture) {// 从手势库中查询匹配的内容，匹配的结果可能包括多个相似的结果，匹配度高的结果放在最前面ArrayList<Prediction> predictions = mGestureLib.recognize(gesture);     if (predictions.size() > 0) {Prediction prediction = (Prediction) predictions.get(0);// 匹配的手势if (prediction.score > 1.0) { // 越匹配score的值越大，最大为10Toast.makeText(GesturePerformedActivity.this,prediction.name, Toast.LENGTH_SHORT).show();}}}});if (mGestureLib == null) {mGestureLib = GestureLibraries.fromFile(mStoreFile);mGestureLib.load();}}}

示例下载

/**

* @author 张兴业

* http://blog.csdn.net/xyz_lmn

* 我的新浪微博：@张兴业TBOW

最后还有点问题，就是多笔画识别问题，这里没有很好的解决，使用OnGesturePerformedListener接听结束，有的多笔画会识别失败，尤其简单的横线竖线组合，复杂的却没有问题。如果使用GestureOverlayView.OnGestureListener监听结束，每一笔画都会调用，不能处理未知笔画数的识别。如果哪位同学完美解决了多笔画问题，请多指教，谢谢。