android.widget.RelativeLayout 无法转换为 android.widget.ImageButton

Posted 2023-04-18

【中文标题】android.widget.RelativeLayout 无法转换为 android.widget.ImageButton

【英文标题】：android.widget.RelativeLayout cannot be cast to android.widegt.ImageButton

【发布时间】：2015-12-30 15:30:14

【问题描述】：

嘿，我想编写一个即时通讯程序，我想使用ImageButton 来确认在聊天中发送消息。但是当我尝试使用ImageButton 时，我遇到了以下问题：

java.lang.RuntimeException: Unable to start activity ComponentInfocom.secmess.secmess/com.secmess.secmess.Erik_Kartenberg: java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.widget.ImageButton
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2328)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2386)
            at android.app.ActivityThread.access$900(ActivityThread.java:169)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1277)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5476)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.widget.ImageButton
            at com.secmess.secmess.Erik_Kartenberg.onCreate(Erik_Kartenberg.java:23)
            at android.app.Activity.performCreate(Activity.java:5451)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2292)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2386)
            at android.app.ActivityThread.access$900(ActivityThread.java:169)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1277)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5476)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)
            at dalvik.system.NativeStart.main(Native Method)
10-02 13:50:38.717  16820-16820/? I/Process﹕ Sending signal. PID: 16820 SIG: 9

这里是活动代码

    package com.secmess.secmess;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;

public class Erik_Kartenberg extends Activity 

    private EditText nachricht;
    private TextView textout;
    private ImageButton sendbutton;

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

        sendbutton = (ImageButton) findViewById(R.id.imagebuutonsend);
        sendbutton.setOnClickListener(new View.OnClickListener() 
            @Override
            public void onClick(View v) 
                nachricht = (EditText) findViewById(R.id.editTextwithhint);
                textout = (TextView) findViewById(R.id.textoutviewer);
                textout.setText(nachricht.getText());
                nachricht.setText("");

            
        );

    

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

    @Override
    public boolean onOptionsItemSelected(MenuItem item) 
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) 
            return true;
        

        return super.onOptionsItemSelected(item);
    

【问题讨论】：

添加你的布局文件

请用英文提问！

哦，好吧，对不起。我想我可以用德语问

发布您的 layout.xml 文件

【参考方案1】：

下次尝试用英文写你的问题:) 这里是一个英文论坛。

对于您的问题：您尝试将 RelativeLayout 转换为 ImageButton。大概就在这一行：

    sendbutton = (ImageButton) findViewById(R.id.imagebuutonsend);

检查您的activity_erik__kartenberg 布局，如果imagebuutonsend 真的是<Imagebutton .../> 而不是<RelativeLayout .../>。

【参考方案2】：

您确定“R.id.imagebuutonsend”是一个 imageView 吗？您正在尝试将 RelativeLayout 转换为 ImageView。检查你的布局，“R.id.imagebuutonsend”可能是一个RelativeLayout。