在父级或祖先上下文中找不到方法

Question

我处理这个问题已有一段时间了，研究了我可以找到的所有相关问题，例如：这个，这个和这个。您能帮我解决这个错误吗？这是logcat抛出的唯一一个。

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>

Answer 1

定义onClick在xml您需要定义它特定视图方式在这里ImageButton你不能在该方法两个参数。

您的错误还表示 无法找到方法playPauseMusic（View） 意味着编译器需要 带有单个参数View_的 _公共方法
，而您有两个参数：View＆ImageButton。

这就是为什么您得到该错误的原因。只需从方法中删除一个参数，它将起作用。

像这样做 ：

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);
    }
}

再写
一遍android:onClick="playPauseMusic"意味着该方法playPauseMusic将在Button单击时调用，因此您已经定义了Button单击，因此
无需在方法内部定义它 ，playPause.setOnClickListener因此我删除了该代码。