无法在父级或祖先上下文中找到方法 [英] Could not find method in parent or ancestor context

问题描述

我一直在处理这个问题，并查看了我能找到的所有相关问题，例如： this this ， this ， this this 。你能帮我纠正这个错误吗？它是logcat抛出的唯一一个。

I've been dealing with this problem for awhile and have looked at all the relevant questions I could find, such as: this one, this one, and this one. Could you help me correct this error? It's the only one being thrown by the logcat.

java.lang.IllegalStateException: Could not find method playPauseMusic(View) in a parent or
ancestor Context for android:onClick attribute defined on view class
android.support.v7.widget.AppCompatImageButton with id 'playPause'

相关代码：

radio.java

package com.example.jacob.wutk;

import android.media.AudioManager;
import android.media.MediaPlayer;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageButton;

import java.io.IOException;

public class radio extends AppCompatActivity {

    /** Called when the user touches the button */

    public void playPauseMusic (View view, final ImageButton playPause) throws IOException {
        String url = "http://streamer.cci.utk.edu:8000/wutk-vorbis"; // your URL here
        final MediaPlayer mediaPlayer = new MediaPlayer();

        mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {

            public void onPrepared(MediaPlayer mediaPlayer){
                mediaPlayer.start();
            }
        });

        playPause.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view) {
                if (mediaPlayer.isPlaying()) {
                    mediaPlayer.pause();
                    playPause.setImageResource(R.drawable.play1);
                } else {
                    playPause.setImageResource(R.drawable.pause1);
                }
            }
        });
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mediaPlayer.setDataSource(url);
        mediaPlayer.prepareAsync();
    }

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

activity_radio.xml

    <?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    tools:context="com.example.jacob.wutk.radio">
    <ImageView
        android:id="@+id/imageView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="left|center_vertical"
        android:scaleType="centerCrop"
        android:src="@drawable/background_mic1"/>

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:paddingBottom="1.0dip"
        android:paddingLeft="4.0dip"
        android:paddingRight="4.0dip"
        android:paddingTop="5.0dip">
       <ImageButton
           android:id="@+id/playPause"
           android:layout_width="0.0dip"
           android:layout_height="wrap_content"
           android:layout_weight="1.0"
           android:background="?android:selectableItemBackground"
           android:clickable="true"
           android:onClick="playPauseMusic"
           android:scaleType="fitCenter"
           android:src="@drawable/play1"/>
       <ImageView
           android:layout_width="0.0dip"
           android:layout_height="fill_parent"
           android:layout_marginRight="5dp"
           android:layout_weight="1.0"
           android:background="?android:selectableItemBackground"
           android:scaleType="fitCenter"
           android:src="@drawable/logo"/>

    </LinearLayout>

</FrameLayout>

推荐答案

定义 onClick in xml 表示你需要为特定视图定义它是 ImageButton 你不能有两个该方法中的参数。

Defining onClick in xml means you need to define it for a particular view here is ImageButton you can not have two arguments in that method.

你的错误也说找不到方法playPauseMusic（View）意味着编译器需要一个单参数的方法查看您有两个参数的位置查看& ImageButton 这就是您收到该错误的原因所在。只需从方法中删除一个参数即可。

Your error is also saying that Could not find method playPauseMusic(View) means compiler needs a methods with single parameter View where as you were having two parameters View & ImageButton this is the reason why you where getting that error. Just remove one argument from the method and it will work.

这样做：

public class radio extends AppCompatActivity {

/** Called when the user touches the button */

public void playPauseMusic (View playPause) {
    String url = "http://streamer.cci.utk.edu:8000/wutk-vorbis"; // your URL here
    final MediaPlayer mediaPlayer = new MediaPlayer();

    mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {

        public void onPrepared(MediaPlayer mediaPlayer){
            mediaPlayer.start();
        }
    });


    if (mediaPlayer.isPlaying()) {
         mediaPlayer.pause();
         ((ImageButton)playPause).setImageResource(R.drawable.play1);
    } else {
        ((ImageButton)playPause).setImageResource(R.drawable.pause1);
    }

    mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
    mediaPlayer.setDataSource(url);
    mediaPlayer.prepareAsync();
}

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

还有一件事要写 android ：onClick =playPauseMusic表示方法 playPauseMusic 将在按钮点击时被调用，因此您已经定义了一个按钮点击，因此不需要通过 playPause.setOnClickListener 在方法中定义它，所以我删除了该代码。

One more thing writing android:onClick="playPauseMusic" means the method playPauseMusic will be called on Button click so you have already defined a button click so no need to define it inside the method by playPause.setOnClickListener so I have removed that code.

这篇关于无法在父级或祖先上下文中找到方法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！