我使用 startAnimation(Animation) 编写了一个显示自定义 ImageView 的 Android 应用程序，该应用程序会定期自行旋转。该应用程序运行良好，但如果我创建类型为 ActivityInstrumentationTestCase2 的 JUnit 测试并且测试调用 getActivity()，则调用 getActivity()在应用程序进入后台之前永远不会返回(例如，按下设备的主页按钮)。

经过长时间的挫折，我发现如果我在自定义 ImageView< 中注释掉对="">startAnimation(Animation) 的调用，getActivity() 会立即返回类。但这会破坏我自定义 ImageView 的目的，因为我确实需要为它设置动画。

谁能告诉我为什么 getActivity() 在我的 JUnit 测试期间阻塞，但只有在使用 startAnimation 时才阻塞？提前感谢任何可以提出解决方法或告诉我我做错了什么的人。

注意:该解决方案至少需要使用 Android API 级别 10。

这是运行它所需的所有源代码(将任何 PNG 图像放在 res/drawable 中并命名为 the_image.png):

activity_main.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <com.example.rotatingimageviewapp.RotatingImageView 
        android:id="@+id/rotatingImageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/the_image" />

</RelativeLayout>

主要 Activity .java:

package com.example.rotatingimageviewapp;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends Activity {

    private RotatingImageView rotatingImageView = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        rotatingImageView = (RotatingImageView) findViewById(
                R.id.rotatingImageView);
        rotatingImageView.startRotation();
    }

    @Override
    protected void onPause() {
        super.onPause();
        rotatingImageView.stopRotation();
    }

    @Override
    protected void onResume() {
        super.onResume();
        rotatingImageView.startRotation();
    }

}

RotatingImageView.java(自定义ImageView):

package com.example.rotatingimageviewapp;

import java.util.Timer;
import java.util.TimerTask;

import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.animation.Animation;
import android.view.animation.RotateAnimation;
import android.widget.ImageView;

public class RotatingImageView extends ImageView {

    private static final long ANIMATION_PERIOD_MS = 1000 / 24;

    //The Handler that does the rotation animation
    private final Handler handler = new Handler() {

        private float currentAngle = 0f;
        private final Object animLock = new Object();
        private RotateAnimation anim = null;

        @Override
        public void handleMessage(Message msg) {
            float nextAngle = 360 - msg.getData().getFloat("rotation");
            synchronized (animLock) {
                anim = new RotateAnimation(
                        currentAngle,
                        nextAngle,
                        Animation.RELATIVE_TO_SELF,
                        .5f,
                        Animation.RELATIVE_TO_SELF,
                        .5f);
                anim.setDuration(ANIMATION_PERIOD_MS);
                /**
                 * Commenting out the following line allows getActivity() to
                 * return immediately!
                 */
                startAnimation(anim);
            }

            currentAngle = nextAngle;
        }

    };

    private float rotation = 0f;
    private final Timer timer = new Timer(true);
    private TimerTask timerTask = null;

    public RotatingImageView(Context context) {
        super(context);
    }

    public RotatingImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public RotatingImageView(Context context, AttributeSet attrs,
            int defStyle) {
        super(context, attrs, defStyle);
    }

    public void startRotation() {
        stopRotation();

        /**
         * Set up the task that calculates the rotation value
         * and tells the Handler to do the rotation
         */
        timerTask = new TimerTask() {

            @Override
            public void run() {
                //Calculate next rotation value
                rotation += 15f;
                while (rotation >= 360f) {
                    rotation -= 360f; 
                }

                //Tell the Handler to do the rotation
                Bundle bundle = new Bundle();
                bundle.putFloat("rotation", rotation);
                Message msg = new Message();
                msg.setData(bundle);
                handler.sendMessage(msg);
            }

        };
        timer.schedule(timerTask, 0, ANIMATION_PERIOD_MS);
    }

    public void stopRotation() {
        if (null != timerTask) {
            timerTask.cancel();
        }
    }

}

MainActivityTest.java:

package com.example.rotatingimageviewapp.test;

import android.app.Activity;
import android.test.ActivityInstrumentationTestCase2;

import com.example.rotatingimageviewapp.MainActivity;

public class MainActivityTest extends
        ActivityInstrumentationTestCase2<MainActivity> {

    public MainActivityTest() {
        super(MainActivity.class);
    }

    protected void setUp() throws Exception {
        super.setUp();
    }

    protected void tearDown() throws Exception {
        super.tearDown();
    }

    public void test001() {
        assertEquals(1 + 2, 3 + 0);
    }

    public void test002() {
        //Test hangs on the following line until app goes to background
        Activity activity = getActivity();
        assertNotNull(activity);
    }

    public void test003() {
        assertEquals(1 + 2, 3 + 0);
    }

}

最佳答案

不知道你们有没有解决这个问题。 但这是我的解决方案，只需覆盖方法 getActivity():

@Override
    public MyActivity getActivity() {
        if (mActivity == null) {
            Intent intent = new Intent(getInstrumentation().getTargetContext(), MyActivity.class);
            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            // register activity that need to be monitored.
            monitor = getInstrumentation().addMonitor(MyActivity.class.getName(), null, false);
            getInstrumentation().getTargetContext().startActivity(intent);
            mActivity = (MyActivity) getInstrumentation().waitForMonitor(monitor);
            setActivity(mActivity);
        }
        return mActivity;
    }

关于android - 当自定义 ImageView 调用 startAnimation(Animation) 时，为什么 getActivity() 在 JUnit 测试期间阻塞？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20860832/