android创建手势识别示例代码

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

代码如下:

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

代码如下:

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

代码如下:

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。

代码如下:

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();
  }
 }

}