Question

这是我的代码：

package com.example.userpage;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class UserPage extends Activity {

     String tv,tv1;
    EditText name,pass;
     TextView x,y;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
         Button button = (Button) findViewById(R.id.widget44);
        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

                name.setText(" ");
                pass.setText(" ");
            }
        });

        x = (TextView) findViewById(R.id.widget46);
        y = (TextView) findViewById(R.id.widget47);
         name = (EditText)findViewById(R.id.widget41);
         pass = (EditText)findViewById(R.id.widget42);
        Button button1 = (Button) findViewById(R.id.widget45);
        button1.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

              tv= name.getText().toString();
               tv1 = pass.getText().toString();
               x.setText(tv);
               y.setText(tv1);
           }
        });
    }
}

这是我的日志猫：

02-16 12:28:32.648: ERROR/AndroidRuntime(1039): FATAL EXCEPTION: main
02-16 12:28:32.648: ERROR/AndroidRuntime(1039): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.userpage/com.example.userpage.UserPage}: java.lang.ClassCastException: android.widget.TextView
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at android.os.Looper.loop(Looper.java:123)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at android.app.ActivityThread.main(ActivityThread.java:4627)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at java.lang.reflect.Method.invokeNative(Native Method)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at java.lang.reflect.Method.invoke(Method.java:521)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at dalvik.system.NativeStart.main(Native Method)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039): Caused by: java.lang.ClassCastException: android.widget.TextView
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at com.example.userpage.UserPage.onCreate(UserPage.java:34)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
02-16 12:28:32.648: ERROR/AndroidRuntime(1039):     ... 11 more
02-16 12:28:32.698: WARN/ActivityManager(67):   Force finishing activity com.example.userpage/.UserPage
02-16 12:28:32.967: DEBUG/dalvikvm(292): GC_EXPLICIT freed 46 objects / 2240 bytes in 6840ms
02-16 12:28:33.247: WARN/ActivityManager(67): Activity pause timeout for HistoryRecord{43ee7b70 com.example.userpage/.UserPage}
02-16 12:28:36.947: INFO/Process(1039): Sending signal. PID: 1039 SIG: 9
02-16 12:28:37.017: INFO/ActivityManager(67): Process com.example.userpage (pid 1039) has died.
02-16 12:28:37.128: WARN/InputManagerService(67): Window already focused, ignoring focus gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@43e872f8
02-16 12:28:42.087: DEBUG/dalvikvm(176): GC_EXPLICIT freed 156 objects / 11488 bytes in 145ms
02-16 12:28:45.391: WARN/ActivityManager(67): Activity destroy timeout for HistoryRecord{43ee7b70 com.example.userpage/.UserPage}
02-16 12:28:47.177: DEBUG/SntpClient(67): request time failed: java.net.SocketException: Address family not supported by protocol

Answer 1

如果这个

Caused by: java.lang.ClassCastException: android.widget.TextView 02-16 12:28:32.648: ERROR/AndroidRuntime(1039): at com.example.userpage.UserPage.onCreate(UserPage.java:34)

...在您的代码中，然后好像您正在尝试将一些（非textview）对象转换为TextView。尝试在onCreate中设置调试点并检查发生了什么。

<强>更新
您确定R.id.widget46和R.id.widget47是 TextView 还是您意外创建了EditText，因为widget41和widget42是EditTexts。或者是最后两个TextView，并尝试将它们转换为EditTexts。检查一下。

Answer 2

有同样的问题。我的解决方案：只需清理项目并重建它。由于某种原因，R.class没有正确更新。

Answer 3

我遇到了同样的问题。对我有用的解决方案是：

我删除了textview并通过从图形布局拖动新的textview并使用不同的ID命名它来重新创建它。另一个变化是它在xml中的顺序。它已经在顶部，重新创建后它位于xml页面的底部。

之后我没有得到任何类型的异常。

Answer 4

问题也可能是因为TextView被转换为其他东西。我遇到了问题并且有相同的java.lang.ClassCastException。

Answer 5

删除R.java 清洁项目保存文件建设与发展运行

Answer 6

只需将TextView添加到xml文件

即可

类强制转换异常

6 个答案: