java - 按钮 onClickListener 和 textView.setText 在 AlertDialog 中不起作用

Question

所以我试图在SongCompletionListener 上构建自定义AlertDialog，但有一个问题...

如果我删除对话框中存在的按钮的 onClickListeners，将出现 AlertDialog...但是当我添加监听器时会崩溃..

这是对话框的屏幕截图，按钮出现但无法工作，因为我已经删除了监听器:

这是我的代码；

completedSongName = (TextView) findViewById(R.id.completedSongName);
        playAnotherSong   = (Button) findViewById(R.id.buttonPlayAnotherSong);
        replayCurrentsong = (Button) findViewById(R.id.buttonPlayAgain);
        tstBtn = (Button) findViewById(R.id.testBtn);

        // ON COMPLETE LISTENERS
        onCompletionDialog = new Dialog(this);

        testSong.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mp) {
                onCompletionDialog.setContentView(R.layout.songcompletedialog);
                completedSongName.setText("testSong");

                playAnotherSong.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        onCompletionDialog.dismiss();
                    }
                });

                replayCurrentsong.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        testSong.start();
                    }
                });
                onCompletionDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
                onCompletionDialog.show();
            }
        });```

这是 XML

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginLeft="5dp"
    android:layout_marginRight="5dp"
    android:gravity="center">


    <android.support.v7.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:cardCornerRadius="20dp"
        app:cardBackgroundColor="@color/colorGreenLight"
        android:layout_alignParentTop="true"
        android:layout_alignParentStart="true">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:orientation="vertical"
                android:layout_marginTop="25dp"
                android:layout_marginBottom="25dp">

                <ImageView
                    android:id="@+id/musicIconFinished"
                    android:layout_width="64dp"
                    android:layout_height="64dp"
                    android:padding="7sp"
                    android:layout_centerHorizontal="true"
                    android:layout_marginStart="10sp"
                    android:background="@drawable/circle_dark_green"
                    android:src="@drawable/ic_library_music_white" />

                <TextView
                    android:id="@+id/completedTextLabel"
                    android:layout_below="@+id/musicIconFinished"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginStart="20dp"
                    android:layout_marginEnd="20dp"
                    android:textAlignment="center"
                    android:textStyle="bold"
                    android:textSize="20sp"
                    android:textColor="@color/colorGreen"
                    android:layout_marginTop="20dp"
                    android:text="Completed"
                    android:fontFamily="@font/productsansregular"/>


                <TextView
                    android:id="@+id/completedSongName"
                    android:layout_below="@+id/completedTextLabel"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginStart="20dp"
                    android:layout_marginEnd="20dp"
                    android:textAlignment="center"
                    android:textStyle="normal"
                    android:textSize="18sp"
                    android:textColor="@color/colorGreen1"
                    android:layout_marginTop="8dp"
                    android:hint="Completed Song Name"
                    android:fontFamily="@font/productsansregular"/>


                <TextView
                    android:id="@+id/songStartTimeLabel"
                    android:layout_below="@+id/completedSongName"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginStart="20dp"
                    android:layout_marginEnd="20dp"
                    android:textAlignment="textStart"
                    android:textStyle="normal"
                    android:textSize="16sp"
                    android:textColor="@color/colorGreen"
                    android:layout_marginTop="14dp"
                    android:text="Start Time:"
                    android:fontFamily="@font/productsansregular"/>


                <TextView
                    android:id="@+id/songStartTime"
                    android:layout_below="@+id/completedSongName"
                    android:layout_toEndOf="@+id/songStartTimeLabel"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginStart="0dp"
                    android:layout_marginEnd="5dp"
                    android:textAlignment="textStart"
                    android:textStyle="normal"
                    android:textSize="16sp"
                    android:textColor="@color/colorGreen1"
                    android:layout_marginTop="14dp"
                    android:hint="Start Time:"
                    android:fontFamily="@font/productsansregular"/>


                <TextView
                    android:id="@+id/songEndTimeLabel"
                    android:layout_below="@+id/songStartTimeLabel"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginStart="20dp"
                    android:layout_marginEnd="20dp"
                    android:textAlignment="textStart"
                    android:textStyle="normal"
                    android:textSize="16sp"
                    android:textColor="@color/colorGreen"
                    android:layout_marginTop="4dp"
                    android:text="Start Time:"
                    android:fontFamily="@font/productsansregular"/>


                <TextView
                    android:id="@+id/songEndTime"
                    android:layout_below="@+id/songStartTime"
                    android:layout_toEndOf="@+id/songEndTimeLabel"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginStart="0dp"
                    android:layout_marginEnd="5dp"
                    android:textAlignment="textStart"
                    android:textStyle="normal"
                    android:textSize="16sp"
                    android:textColor="@color/colorGreen1"
                    android:layout_marginTop="4dp"
                    android:hint="Start Time:"
                    android:fontFamily="@font/productsansregular"/>

                <Button
                    android:layout_width="200dp"
                    android:layout_height="wrap_content"
                    android:id="@+id/buttonPlayAnotherSong"
                    android:layout_below="@id/songEndTime"
                    android:layout_marginTop="20dp"
                    android:layout_centerHorizontal="true"
                    android:text="Play Another Song"
                    android:fontFamily="@font/productsansregular"
                    android:textColor="@color/textColorWhite"
                    android:textSize="14sp"
                    android:background="@drawable/button_background_green"/>

                <Button
                    android:layout_width="200dp"
                    android:layout_height="wrap_content"
                    android:id="@+id/buttonPlayAgain"
                    android:layout_below="@id/buttonPlayAnotherSong"
                    android:layout_marginTop="16dp"
                    android:layout_centerHorizontal="true"
                    android:text="Replay current song"
                    android:fontFamily="@font/productsansregular"
                    android:textColor="@color/textColorWhite"
                    android:textSize="14sp"
                    android:background="@drawable/button_background_green"/>


            </RelativeLayout>

        </LinearLayout>

    </android.support.v7.widget.CardView>


</RelativeLayout>

为了测试代码，我使用了 testButton ..

testButton.onClick ...会出现弹出窗口..

罪魁祸首是:

completedSongName.setText("testSong");

                playAnotherSong.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        onCompletionDialog.dismiss();
                    }
                });

                replayCurrentsong.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        testSong.start();
                    }
                });
                onCompletionDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
                onCompletionDialog.show();
            }

它显示什么错误？

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.innocentapps.musicplayerstrial, PID: 7928
    java.lang.IllegalStateException: Could not execute method for android:onClick
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:390)
        at android.view.View.performClick(View.java:6600)
        at android.view.View.performClickInternal(View.java:6577)
        at android.view.View.access$3100(View.java:781)
        at android.view.View$PerformClick.run(View.java:25912)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6923)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:870)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Method.invoke(Native Method)
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
        at android.view.View.performClick(View.java:6600) 
        at android.view.View.performClickInternal(View.java:6577) 
        at android.view.View.access$3100(View.java:781) 
        at android.view.View$PerformClick.run(View.java:25912) 
        at android.os.Handler.handleCallback(Handler.java:873) 
        at android.os.Handler.dispatchMessage(Handler.java:99) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6923) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:870) 
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
        at com.innocentapps.musicplayertrial.MainActivity.showOnCompletionPopUp(MainActivity.java:564)
        at java.lang.reflect.Method.invoke(Native Method) 
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385) 
        at android.view.View.performClick(View.java:6600) 
        at android.view.View.performClickInternal(View.java:6577) 
        at android.view.View.access$3100(View.java:781) 
        at android.view.View$PerformClick.run(View.java:25912) 
        at android.os.Handler.handleCallback(Handler.java:873) 
        at android.os.Handler.dispatchMessage(Handler.java:99) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6923) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:870) 
I/Process: Sending signal. PID: 7928 SIG: 9

应用程序已终止。

Answer 1

试试这个

 onCompletionDialog = new Dialog(this);
        onCompletionDialog .requestWindowFeature(Window.FEATURE_NO_TITLE);
        onCompletionDialog .setContentView(R.layout.songcompletedialog);
        completedSongName = (TextView)onCompletionDialog.findViewById(R.id.completedSongName);
        playAnotherSong   = (Button)onCompletionDialog.findViewById(R.id.buttonPlayAnotherSong);
        replayCurrentsong = (Button) onCompletionDialog.findViewById(R.id.buttonPlayAgain);
        tstBtn = (Button)onCompletionDialog.findViewById(R.id.testBtn);

并在您希望显示对话框时放置此内容。

 onCompletionDialog.show();