无法暂停活动？

Question

我是一个不熟悉Android开发的新手。我写了这段代码，但是我无法弄清楚导致我的应用程序崩溃的原因。它告诉我活动无法暂停。我确定我漏掉了一些东西。我曾经写过非常相似的代码，过去也起作用，所以我不确定从哪里开始。

SplashActivity.java

public class SplashActivity extends Activity
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_splash);

        ImageView logo = (ImageView) findViewById(R.id.ImageViewLogo);
        Animation twistIn = AnimationUtils.loadAnimation(this, R.anim.twist_in);
        logo.startAnimation(twistIn);
        twistIn.setAnimationListener(new AnimationListener()
        {
            public void onAnimationStart(Animation animation)
            {
                return; // do nothing
            }
            public void onAnimationRepeat(Animation animation)
            {
                return; // do nothing
            }
            public void onAnimationEnd(Animation animation)
            {
                startActivity(new Intent(SplashActivity.this, MenuActivity.class));
                SplashActivity.this.finish();
            }
        });
    }

    @Override
    protected void onPause()
    {
        super.onPause();

        TextView logo = (TextView) findViewById(R.id.ImageViewLogo);
        logo.clearAnimation();
    }
}

这里是LogCat的报错信息：

04-04 02:09:10.460: W/dalvikvm(12531): threadid=1: thread exiting with uncaught exception (group=0x4001e578)
04-04 02:09:10.480: E/AndroidRuntime(12531): FATAL EXCEPTION: main
04-04 02:09:10.480: E/AndroidRuntime(12531): java.lang.RuntimeException: Unable to pause activity {com.swapwords/com.swapwords.SplashActivity}: java.lang.ClassCastException: android.widget.ImageView
04-04 02:09:10.480: E/AndroidRuntime(12531):    at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2358)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2315)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at android.app.ActivityThread.handlePauseActivity(ActivityThread.java:2295)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at android.app.ActivityThread.access$1700(ActivityThread.java:117)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:942)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at android.os.Handler.dispatchMessage(Handler.java:99)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at android.os.Looper.loop(Looper.java:130)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at android.app.ActivityThread.main(ActivityThread.java:3691)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at java.lang.reflect.Method.invokeNative(Native Method)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at java.lang.reflect.Method.invoke(Method.java:507)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:912)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:670)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at dalvik.system.NativeStart.main(Native Method)
04-04 02:09:10.480: E/AndroidRuntime(12531): Caused by: java.lang.ClassCastException: android.widget.ImageView
04-04 02:09:10.480: E/AndroidRuntime(12531):    at com.swapwords.SplashActivity.onPause(SplashActivity.java:57)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at android.app.Activity.performPause(Activity.java:3893)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at android.app.Instrumentation.callActivityOnPause(Instrumentation.java:1194)
04-04 02:09:10.480: E/AndroidRuntime(12531):    at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2345)
04-04 02:09:10.480: E/AndroidRuntime(12531):    ... 12 more
04-04 02:09:12.452: I/dalvikvm(12531): threadid=4: reacting to signal 3
04-04 02:09:12.452: I/dalvikvm(12531): Wrote stack traces to '/data/anr/traces.txt'
04-04 02:09:18.878: I/dalvikvm(12531): threadid=4: reacting to signal 3
04-04 02:09:18.878: I/dalvikvm(12531): Wrote stack traces to '/data/anr/traces.txt'

我只是迷失了方向。

- Michael Zimmerman

Answer 1

使用

ImageView logo = (ImageView) findViewById(R.id.ImageViewLogo);

替代

TextView logo = (TextView) findViewById(R.id.ImageViewLogo);

由于您当前正在尝试将在XML布局中添加的 ImageView 强制转换为 TextView ，因此应该在 onPause() 方法中进行更改。

- ρяσѕρєя K

Answer 2

您正在尝试使用TextView引用ImageView，因此它会抛出ClassCastException

将其更改为

 TextView logo = (TextView) findViewById(R.id.ImageViewLogo);

转换为：

 ImageView logo = (ImageView) findViewById(R.id.ImageViewLogo);

- Pragnani

Answer 3

在Oncreate()方法中看到这行代码。

 ImageView logo = (ImageView) findViewById(R.id.ImageViewLogo);

在onPause()方法中，您已经使用了TextView而不是像上面那样的ImageView

    TextView logo = (TextView) findViewById(R.id.ImageViewLogo);

所以这个错误是类转换异常...将 TextView 更改为 ImageView。

- Nirali