Question

您好我是Android应用程序的新手。我想为我的图像添加缩放效果。我从[https://github.com/jasonpolites/gesture-imageview] [1]中获取了一个示例教程，并从那里复制了示例代码。但是当我试图在eclipse中运行java代码时，会引发异常。代码附在此处。

ViewIndia.java

public class ViewIndia extends Activity {

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

                LayoutParams params = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);

                GestureImageView view = new GestureImageView(this);
                view.setImageResource(R.drawable.india);
                view.setLayoutParams(params);

                ViewGroup lout = (ViewGroup) findViewById(R.id.gestureImageView);

                lout.addView(view);
            }

        @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.view_india, menu);
        return true;
    }

}

activity_view_india.xml

<RelativeLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:gesture-image="http://schemas.polites.com/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
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=".ViewIndia" >
    <com.polites.android.GestureImageView
    android:id="@+id/gestureImageView"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:src="@drawable/india"
    gesture-image:min-scale="0.1"
    gesture-image:max-scale="10.0"
    gesture-image:strict="true"/>

和日志文件

08-05 01:41:53.671: E/AndroidRuntime(1001): FATAL EXCEPTION: main
08-05 01:41:53.671: E/AndroidRuntime(1001): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.viewindia/com.example.viewindia.ViewIndia}: java.lang.ClassCastException: com.polites.android.GestureImageView cannot be cast to android.view.ViewGroup
08-05 01:41:53.671: E/AndroidRuntime(1001):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at android.os.Handler.dispatchMessage(Handler.java:99)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at android.os.Looper.loop(Looper.java:137)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at android.app.ActivityThread.main(ActivityThread.java:5103)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at java.lang.reflect.Method.invokeNative(Native Method)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at java.lang.reflect.Method.invoke(Method.java:525)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at dalvik.system.NativeStart.main(Native Method)
08-05 01:41:53.671: E/AndroidRuntime(1001): Caused by: java.lang.ClassCastException: com.polites.android.GestureImageView cannot be cast to android.view.ViewGroup
08-05 01:41:53.671: E/AndroidRuntime(1001):     at com.example.viewindia.ViewIndia.onCreate(ViewIndia.java:25)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at android.app.Activity.performCreate(Activity.java:5133)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
08-05 01:41:53.671: E/AndroidRuntime(1001):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
08-05 01:41:53.671: E/AndroidRuntime(1001):     ... 11 more

请帮助我摆脱错误。

Answer 1

ViewGroup lout = (ViewGroup) findViewById(R.id.gestureImageView);

您的gestureImageView不是ViewGroup。它扩展到哪一类？是视图吗？如果是，请使用

View lout = (View) findViewById(R.id.gestureImageView);

使用gestureImageView和ViewGroup时Android运行时异常

1 个答案: