android創建手勢識別示例代碼

這篇的內容使用到的是android.gesture包，具體的例子參考的是Sample中GestureBuilder程序。

1、手勢創建
手勢創建主要用到GestureOverlayView和GestureLibrary。GestureOverlayView的父類為android.widget.FrameLayout，是手勢繪圖區。GestureLibrary類主要對手勢進行保存、刪除等操作的，存放手勢的倉庫。下面給出創建手勢的例子，如下圖，可以定義如圖手勢打開csdn.net

1.1、創建繪圖區

復制代碼 代碼如下:
 GestureOverlayView overlay = (GestureOverlayView) findViewById(R.id.gestures_overlay);

overlay.setGestureStrokeType(GestureOverlayView.GESTURE_STROKE_TYPE_MULTIPLE); 

overlay.setFadeOffset(2000);  //多筆畫每兩次的間隔時間
overlay.setGestureColor(Color.CYAN);//畫筆顏色
overlay.setGestureStrokeWidth(6);//畫筆粗細值

overlay.addOnGestureListener(new GesturesProcessor());

1.2、監聽繪制

復制代碼 代碼如下:
 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、保存手勢

復制代碼 代碼如下:
 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;
            }

            /**
             * 獲取手勢庫
             *   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、手勢識別

手勢識別也是經過創建繪圖區、監聽繪制、比對結果三個過程，這裡直接給出代碼。

復制代碼 代碼如下:
public class GesturePerformedActivity extends Activity {

 private final File mStoreFile = new File(
   Environment.getExternalStorageDirectory(), "gestures");

 // 手勢庫
 GestureLibrary mGestureLib;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  // TODO Auto-generated method stub
  super.onCreate(savedInstanceState);

  setContentView(R.layout.gesture_perform);
  // 手勢畫板
  GestureOverlayView gestures = (GestureOverlayView) findViewById(R.id.gestures_overlay);

  gestures.setGestureStrokeType(GestureOverlayView.GESTURE_STROKE_TYPE_MULTIPLE);

  gestures.setFadeOffset(2000); // 多筆畫每兩次的間隔時間
  gestures.setGestureColor(Color.CYAN);// 畫筆顏色
  gestures.setGestureStrokeWidth(6);// 畫筆粗細值

  // 手勢識別的監聽器
  gestures.addOnGesturePerformedListener(new GestureOverlayView.OnGesturePerformedListener() {
   @Override
   public void onGesturePerformed(GestureOverlayView overlay,
     Gesture gesture) {
    // 從手勢庫中查詢匹配的內容，匹配的結果可能包括多個相似的結果，匹配度高的結果放在最前面
    ArrayList<Prediction> predictions = mGestureLib
      .recognize(gesture);  
    if (predictions.size() > 0) {
     Prediction prediction = (Prediction) predictions.get(0);
     // 匹配的手勢
     if (prediction.score > 1.0) { // 越匹配score的值越大，最大為10
      Toast.makeText(GesturePerformedActivity.this,
        prediction.name, Toast.LENGTH_SHORT).show();
     }
    }
   }
  });

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

}