public class TestActivity extends Activity implements OnGesturePerformedListener {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mLibrary = GestureLibraries.fromRawResource(this, R.raw.gestures);
GestureOverlayView gestures = (GestureOverlayView) findViewById(R.id.gestureOverlayView1);
gestures.addOnGesturePerformedListener(TestActivity.this);
}
我的 main.xml
<ImageView android:id="@+id/imageView1" android:layout_width="fill_parent" android:layout_height="fill_parent" android:src="@drawable/ic_launcher" /> <android.gesture.GestureOverlayView android:id="@+id/gestureOverlayView1" android:layout_width="fill_parent" android:layout_height="fill_parent" > </android.gesture.GestureOverlayView>
活动.java：
private GestureLibrary mLibrary;
public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture) {
ArrayList<Prediction> predictions = mLibrary.recognize(gesture);
Log.v("performed", "performed");
// We want at least one prediction
if (predictions.size() > 0) {
Prediction prediction = predictions.get(0);
// We want at least some confidence in the result
if (prediction.score > 1.0) {
if (prediction.name.equalsIgnoreCase("right swipe")) {
// do you thing here//
Toast.makeText(TestActivity.this, "rigth",
Toast.LENGTH_SHORT);
} else if (prediction.name.equalsIgnoreCase("left swipe")) {
Toast.makeText(TestActivity.this, "lef",
Toast.LENGTH_SHORT);
}
}
}
}
运行此程序会在 Log 中显示以下内容：
05-17 15:18:52.124: E/AndroidRuntime(17266): FATAL EXCEPTION: main
05-17 15:18:52.124: E/AndroidRuntime(17266): java.lang.RuntimeException: Unable to start activity ComponentInfo{t.e.st/t.e.st.TestActivity}: java.lang.NullPointerException
05-17 15:18:52.124: E/AndroidRuntime(17266): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1768)
05-17 15:18:52.124: E/AndroidRuntime(17266): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1784)
05-17 15:18:52.124: E/AndroidRuntime(17266): at android.app.ActivityThread.access$1500(ActivityThread.java:123)
05-17 15:18:52.124: E/AndroidRuntime(17266): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:939)
05-17 15:18:52.124: E/AndroidRuntime(17266): at android.os.Handler.dispatchMessage(Handler.java:99)
05-17 15:18:52.124: E/AndroidRuntime(17266): at android.os.Looper.loop(Looper.java:130)
05-17 15:18:52.124: E/AndroidRuntime(17266): at android.app.ActivityThread.main(ActivityThread.java:3835)
05-17 15:18:52.124: E/AndroidRuntime(17266): at java.lang.reflect.Method.invokeNative(Native Method)
05-17 15:18:52.124: E/AndroidRuntime(17266): at java.lang.reflect.Method.invoke(Method.java:507)
05-17 15:18:52.124: E/AndroidRuntime(17266): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:847)
05-17 15:18:52.124: E/AndroidRuntime(17266): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605)
05-17 15:18:52.124: E/AndroidRuntime(17266): at dalvik.system.NativeStart.main(Native Method)
05-17 15:18:52.124: E/AndroidRuntime(17266): Caused by: java.lang.NullPointerException
**05-17 15:18:52.124: E/AndroidRuntime(17266): at t.e.st.TestActivity.onCreate(TestActivity.java:26)**
05-17 15:18:52.124: E/AndroidRuntime(17266): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-17 15:18:52.124: E/AndroidRuntime(17266): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1722)
05-17 15:18:52.124: E/AndroidRuntime(17266): ... 11 more
请帮我解决这个问题。
覆盖在 xml 中。所以这不是问题，它说错误在第 26 行。所以它的 abt addOnGesturePerformedListener();