Question

Android告诉我应用程序已经停止了，但我的代码中没有错误。

package com.example.helloandroid;

import android.app.Activity;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.TableLayout;

public class HelloAndroid extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        for(int i = 0; i < 6; i++) {
            TableLayout tl = (TableLayout) findViewById(R.id.T);
            for(int j = 0; j < 6; j++) {
                ImageView img = (ImageView) tl.getChildAt(j);
                img.setImageResource(R.drawable.w);
            }
        }
    }
}

Logcat说：

03-03 19:25:43.550: WARN/dalvikvm(487): threadid=1: thread exiting with uncaught exception (group=0x40015560)
03-03 19:25:43.580: ERROR/AndroidRuntime(487): FATAL EXCEPTION: main
03-03 19:25:43.580: ERROR/AndroidRuntime(487): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.helloandroid/com.example.helloandroid.HelloAndroid}: java.lang.ClassCastException: android.widget.TableRow
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at android.os.Looper.loop(Looper.java:123)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at android.app.ActivityThread.main(ActivityThread.java:3683)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at java.lang.reflect.Method.invokeNative(Native Method)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at java.lang.reflect.Method.invoke(Method.java:507)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at dalvik.system.NativeStart.main(Native Method)
03-03 19:25:43.580: ERROR/AndroidRuntime(487): Caused by: java.lang.ClassCastException: android.widget.TableRow
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at com.example.helloandroid.HelloAndroid.onCreate(HelloAndroid.java:17)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
03-03 19:25:43.580: ERROR/AndroidRuntime(487):     ... 11 more

编辑：问题在于布局：

package com.example.helloandroid;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.TableLayout;
import android.widget.TableRow;

public class HelloAndroid extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        for(int i = 0; i < 7; i++) {
            TableLayout tl = (TableLayout) findViewById(R.id.T);
            TableRow tr = (TableRow) tl.getChildAt(i);
            for(int j = 0; j < 7; j++) {
                ImageView img = (ImageView) tr.getChildAt(j);
                img.setImageResource(R.drawable.w);
            }
        }
    }
}

Answer 1

查看Logcat以查看将查明故障位置的堆栈跟踪。

我的猜测是findViewById（）或getChildAt（）返回null，即你的布局不是你想象的那样。

Answer 2

TableLayout tl = (TableLayout) findViewById(R.id.T);：

findViewById(R.id.T)的结果很可能不是TableLayout类型（但不是null）。尝试打印出findViewById(R.id.T).getClass().getName();

这就是我告诉我的：

Caused by: java.lang.ClassCastException: android.widget.TableRow
     at com.example.helloandroid.HelloAndroid.onCreate(HelloAndroid.java:17)

Answer 3

由于 layout.xml 编码错误，我收到此错误。而不是......

<?xml version="1.0" encoding="iso-8859-1"?>

......应该是我的情况：

<?xml version="1.0" encoding="utf-8"?>

很难想出这个。

应用程序意外停止

3 个答案: