Java 在父或祖先上下文中找不到方法
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/38392359/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Could not find method in parent or ancestor context
提问by McLemore
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.
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 one，this one和this one。你能帮我纠正这个错误吗？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'
Relevant code:
相关代码：
radio.java
电台.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
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>
采纳答案by Janki Gadhiya
Defining onClickin xmlmeans you need to define it for a particular view here is ImageButtonyou can not have two arguments in that method.
定义onClickinxml意味着您需要在此处为特定视图定义它，因为ImageButton该方法中不能有两个参数。
Your error is also saying that Could not find method playPauseMusic(View)means compiler needs a methods with single parameter Viewwhere as you were having two parameters View& ImageButtonthis is the reason why you where getting that error. Just remove one argument from the method and it will work.
您的错误还说找不到方法 playPauseMusic(View)意味着编译器需要一个具有单个参数的方法View，因为您有两个参数View，ImageButton这就是您收到该错误的原因。只需从方法中删除一个参数，它就会起作用。
Do it like this :
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);
}
}
One more thing writing android:onClick="playPauseMusic"means the method playPauseMusicwill be called on Button click so you have already defined a button click so no need to define it inside the methodby playPause.setOnClickListenerso I have removed that code.
另一件事写作android:onClick="playPauseMusic"意味着该方法playPauseMusic将在按钮单击时调用，因此您已经定义了一个按钮单击，因此无需在方法内部定义它，playPause.setOnClickListener因此我删除了该代码。
回答by johnrao07
Your code possibly should start with:
您的代码可能应该以：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_radio);
}
You're specifying onClick in xml
您在 xml 中指定 onClick
android:onClick="playPauseMusic"
So, the method works, you've got inner onClicks too. If they are some views.
因此，该方法有效，您也有内部 onClicks。如果他们有一些看法。
You gotta initialize and get it from the xml in code, for ex-
您必须初始化并从代码中的 xml 中获取它，例如-
If you have ImageButton in xml, whose id is "playPause"
如果您在 xml 中有 ImageButton，其 id 为“playPause”
ImageButton playPause; //Declare it here if you wanna use it in all other places in the class or outside of your class
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_radio);
playPause = (ImageButton)findViewById(R.id.playPause);
playPause.setOnClickListener(new View.OnClickListener(){
public void onClick(View view) {
//OnCLick Stuff
}
});
}
In Your case, you've got onClick attribute in xml and another onCLick in code. You Use one.
在您的情况下，您在 xml 中有 onClick 属性，在代码中有另一个 onCLick 属性。你用一个。
