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
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GestureOverlayView overlay = (GestureOverlayView) findViewById(R.id.gestures_overlay);
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overlay.setGestureStrokeType(GestureOverlayView.GESTURE_STROKE_TYPE_MULTIPLE);
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overlay.setFadeOffset(2000); //多笔画每两次的间隔时间
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overlay.setGestureColor(Color.CYAN);//画笔颜色
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overlay.setGestureStrokeWidth(6);//画笔粗细值
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overlay.addOnGestureListener(new GesturesProcessor());
1.2、监听绘制
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privateclass GesturesProcessor implements GestureOverlayView.OnGestureListener {
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publicvoid onGestureStarted(GestureOverlayView overlay, MotionEvent event) {
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mDoneButton.setEnabled(false);
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mGesture = null;
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}
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publicvoid onGesture(GestureOverlayView overlay, MotionEvent event) {
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}
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publicvoid onGestureEnded(GestureOverlayView overlay, MotionEvent event) {
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mGesture = overlay.getGesture();
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if (mGesture.getLength() < LENGTH_THRESHOLD) {
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overlay.clear(false);
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}
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mDoneButton.setEnabled(true);
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}
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publicvoid onGestureCancelled(GestureOverlayView overlay, MotionEvent event) {
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}
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}
1.3、保存手势
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publicvoid addGesture(View v) {
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if (mGesture != null) {
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final TextView input = (TextView) findViewById(R.id.gesture_name);
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final CharSequence name = input.getText();
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if (name.length() == 0) {
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input.setError(getString(R.string.error_missing_name));
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return;
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}
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/**
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* 获取手势库
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* private final File mStoreFile = new File(Environment.getExternalStorageDirectory(), "gestures");
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* GestureLibrary sStore = GestureLibraries.fromFile(mStoreFile);
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*
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*/
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final GestureLibrary store = GestureBuilderActivity.getStore();
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store.addGesture(name.toString(), mGesture);
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store.save();
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setResult(RESULT_OK);
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final String path = new File(Environment.getExternalStorageDirectory(),
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"gestures").getAbsolutePath();
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Toast.makeText(this, getString(R.string.save_success, path), Toast.LENGTH_LONG).show();
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} else {
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setResult(RESULT_CANCELED);
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}
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finish();
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}
2、手势识别
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publicclass GesturePerformedActivity extends Activity {
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privatefinal File mStoreFile = new File(
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Environment.getExternalStorageDirectory(), "gestures");
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// 手势库
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GestureLibrary mGestureLib;
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@Override
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protectedvoid onCreate(Bundle savedInstanceState) {
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// TODO Auto-generated method stub
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super.onCreate(savedInstanceState);
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setContentView(R.layout.gesture_perform);
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// 手势画板
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GestureOverlayView gestures = (GestureOverlayView) findViewById(R.id.gestures_overlay);
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gestures.setGestureStrokeType(GestureOverlayView.GESTURE_STROKE_TYPE_MULTIPLE);
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gestures.setFadeOffset(2000); // 多笔画每两次的间隔时间
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gestures.setGestureColor(Color.CYAN);// 画笔颜色
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gestures.setGestureStrokeWidth(6);// 画笔粗细值
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// 手势识别的监听器
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gestures.addOnGesturePerformedListener(new GestureOverlayView.OnGesturePerformedListener() {
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@Override
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publicvoid onGesturePerformed(GestureOverlayView overlay,
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Gesture gesture) {
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// 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
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ArrayList<Prediction> predictions = mGestureLib
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.recognize(gesture);
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if (predictions.size() > 0) {
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Prediction prediction = (Prediction) predictions.get(0);
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// 匹配的手势
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if (prediction.score > 1.0) { // 越匹配score的值越大，最大为10
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Toast.makeText(GesturePerformedActivity.this,
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prediction.name, Toast.LENGTH_SHORT).show();
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}
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}
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}
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});
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if (mGestureLib == null) {
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mGestureLib = GestureLibraries.fromFile(mStoreFile);
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mGestureLib.load();
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}
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}
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}
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。
