android手势创建及识别

文章来源：http://www.cnblogs.com/android100/p/android-hand.html

源码:http://files.cnblogs.com/android100/gesture.builder.zip

    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;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.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() {
            @Override
            public 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10
                        Toast.makeText(GesturePerformedActivity.this,
                                prediction.name, Toast.LENGTH_SHORT).show();
                    }
                }
            }
        });

        if (mGestureLib == null) {
            mGestureLib = GestureLibraries.fromFile(mStoreFile);
            mGestureLib.load();
        }
    }

}