Android按钮在活动对话框中不起作用

Posted 2023-04-19

【中文标题】Android按钮在活动对话框中不起作用

【英文标题】：Android Button not working in activity dialog

【发布时间】：2016-08-31 03:06:03

【问题描述】：

我使用 EditText 小部件和 Button 创建了一个活动，并将其显示为一个对话框。它在打开时显示得很好，但是每当我在该活动（对话框之一）内的按钮上设置 onClickListener 时，该活动根本不会打开，并且应用程序崩溃并出现以下错误：

05-05 12:33:26.717 2998-2998/org.ufiministries.app E/androidRuntime: FATAL EXCEPTION: main
                                                                 Process: org.ufiministries.app, PID: 2998
                                                                 java.lang.RuntimeException: Unable to start activity ComponentInfoorg.ufiministries.app/org.ufiministries.app.PostPrayerCommentActivity: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
                                                                     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
                                                                     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
                                                                     at android.app.ActivityThread.-wrap11(ActivityThread.java)
                                                                     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
                                                                     at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                     at android.os.Looper.loop(Looper.java:148)
                                                                     at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                                     at java.lang.reflect.Method.invoke(Native Method)
                                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
                                                                  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
                                                                     at org.ufiministries.app.PostPrayerCommentActivity.onCreate(PostPrayerCommentActivity.java:36)
                                                                     at android.app.Activity.performCreate(Activity.java:6237)
                                                                     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
                                                                     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
                                                                     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
                                                                     at android.app.ActivityThread.-wrap11(ActivityThread.java) 
                                                                     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
                                                                     at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                     at android.os.Looper.loop(Looper.java:148) 
                                                                     at android.app.ActivityThread.main(ActivityThread.java:5417) 
                                                                     at java.lang.reflect.Method.invoke(Native Method) 
                                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
                                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

请帮忙。如果我删除 button.setOnClickListener 对话框将打开

活动代码：

package org.ufiministries.app;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import android.support.v7.app.AppCompatDialog;

public class PostPrayerCommentActivity extends AppCompatActivity implements View.OnClickListener 

private Toolbar toolbar;
private Button btnComment;
private EditText txtPrayer;
private String objectId, requestor, userId;
private String sendPrayerText;

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

    Intent prayerComment = getIntent();
    objectId = prayerComment.getStringExtra("objectId");
    requestor = prayerComment.getStringExtra("requestor");
    //userId = prayerComment.getStringExtra("userId");

    btnComment = (Button) findViewById(R.id.btnSendPrayer);
    txtPrayer = (EditText) findViewById(R.id.prayerTxt);
    this.btnComment.setOnClickListener(this);
    toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    setTitle("Prayer for: " + requestor);




@Override
public void onClick(View v) 
    switch (v.getId()) 
        case R.id.btnSendPrayer:
            sendPrayerText = txtPrayer.getText().toString();
            break;
    

XML 代码：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_
android:layout_
tools:context=".PostPrayerCommentActivity"
xmlns:app1="http://schemas.android.com/apk/res/org.ufiministries.app">

<LinearLayout
    android:id="@+id/linear"
    android:layout_
    android:layout_
    android:orientation="vertical">

    <include
        android:id="@+id/toolbar"
        layout="@layout/tool_bar" />
</LinearLayout>

<LinearLayout
    android:layout_
    android:layout_
    android:padding="@dimen/activity_horizontal_margin"
    android:layout_below="@+id/linear"
    android:orientation="vertical">

    <TextView
        android:id="@+id/prayer_request_article_content"
        android:layout_
        android:layout_centerHorizontal="true"
        android:text="@string/testimonialText"
        android:lines="3"
        android:layout_ />

    <android.support.design.widget.TextInputLayout
        android:id="@+id/phoneLayout"
        android:layout_below="@+id/headerTxtPrayerRequest"
        android:layout_
        android:layout_marginTop="@dimen/text_large_padding"
        app:counterEnabled="true"
        app:counterMaxLength="140"
        app:hintAnimationEnabled="true"
        android:layout_>

        <EditText
            android:id="@+id/prayerTxt"
            android:layout_
            android:layout_
            android:layout_weight="1"
            android:hint="Enter prayer"
            android:minLines="5"
            style="@style/Widget.AppCompat.EditText"
            android:inputType="textMultiLine">

            <requestFocus />
        </EditText>

    </android.support.design.widget.TextInputLayout>

    <Button
        android:id="@+id/prayer_comment_btn"
        android:layout_
        android:layout_
        android:layout_below="@+id/prayer_request_article_date"
        android:layout_gravity="center_horizontal"
        android:paddingRight="48dp"
        android:paddingLeft="48dp"
        android:layout_marginTop="@dimen/text_large_padding"
        android:background="@color/colorPrimary"
        style="@style/ParseLoginUI.Button"
        android:text="Send Prayer" />

</LinearLayout>

【问题讨论】：

显示你的整个代码

检查你是否为按钮编写了这段代码。按钮按钮 = (Button) findViewById(R.id.button);如果您这样做了，请显示您的代码。

@techniqez 包含但仍无法正常工作

【参考方案1】：

改变这个

btnComment = (Button) findViewById(R.id.btnSendPrayer);

到

btnComment = (Button) findViewById(R.id.prayer_comment_btn);

【讨论】：

哦不知道我怎么错过了。感谢您发现我。

如果它对你有用，你应该接受这个答案:)