如何在單擊按鈕時阻止應用程序崩潰？

Question

當我嘗試單擊具有onClick方法的按鈕時，應用程序崩潰，錯誤提示“無法為android：onClick執行方法”。 當我在文本輸入中添加onClick方法時，也會發生這種情況。

這是我的代碼：

public class MainActivity extends AppCompatActivity {

// 0= yellow, 1=Red
int activePlayer=0;

boolean gameIsActive=true;


// 2 means un played
 int[] gameState={2, 2, 2, 2, 2, 2, 2, 2, 2};

int[][] winnigPossitions={{0,1,2},{3,4,5},{6,7,8},{0,3,6},{1,4,7},{2,5,8},{0,4,8},{2,4,6}};

public void dropIn(View view)
{

    final ImageView counter=(ImageView) view;
    int tapCounter=Integer.parseInt(counter.getTag().toString());

    if (gameState[tapCounter]==2 && gameIsActive)
    {
        gameState[tapCounter]=activePlayer;

        if (activePlayer == 0) {
            counter.setImageResource(R.drawable.circle);
            counter.animate().scaleY(0.5f).scaleX(0.5f).setDuration(50);
            counter.animate().scaleX(6f).scaleY(6f).setDuration(50);
            counter.animate().scaleY(0.6f).scaleX(0.6f).setDuration(50);
            activePlayer = 1;
        } else {
            counter.setImageResource(R.drawable.cross);
            counter.animate().scaleY(0.5f).scaleX(0.5f).setDuration(50);
            counter.animate().scaleX(6f).scaleY(6f).setDuration(50);
            counter.animate().scaleY(0.6f).scaleX(0.6f).setDuration(50);
            activePlayer = 0;
        }

        for (int[] winnigPossitions:winnigPossitions)
        {
            if (gameState[winnigPossitions[0]]==gameState[winnigPossitions[1]] &&
                    gameState[winnigPossitions[1]]==gameState[winnigPossitions[2]] &&
                    gameState[winnigPossitions[0]]!=2)
            {
                gameIsActive=false;
                LinearLayout layout=findViewById(R.id.linearLayout);
                layout.setVisibility(View.VISIBLE);

            }

            else
            {
                boolean gameIsOver=true;

                for (int counterState : gameState)
                {
                    if (counterState==2)
                    {
                        gameIsOver=false;
                    }
                }

                if (gameIsOver)
                {
                    TextView txtWon=findViewById(R.id.txtWon);

                    txtWon.setText("It's a Draw");
                    LinearLayout layout=findViewById(R.id.linearLayout);
                    layout.setVisibility(view.VISIBLE);

                }
            }


        }

    }


}






public void playAgain(View view)
{
    gameIsActive=true;
    LinearLayout layout=findViewById(R.id.linearLayout);
    layout.setVisibility(View.INVISIBLE);

     activePlayer=0;

    for (int i=0;i<gameState.length;i++)
    {
        gameState[i]=2;
    }

    GridLayout gridLayout=findViewById(R.id.gridLayout);
    for (int i=0;i<gridLayout.getChildCount();i++)
    {
        ((ImageView)gridLayout.getChildAt(i)).setImageResource(0);
    }

}

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

}

單擊按鈕時，這是完整的錯誤：

java.lang.IllegalStateException: Could not execute method for android:onClick
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:390)
        at android.view.View.performClick(View.java:6199)
        at android.widget.TextView.performClick(TextView.java:11090)
        at android.view.View$PerformClick.run(View.java:23647)
        at android.os.Handler.handleCallback(Handler.java:751)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6682)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Method.invoke(Native Method)
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
        at android.view.View.performClick(View.java:6199) 
        at android.widget.TextView.performClick(TextView.java:11090) 
        at android.view.View$PerformClick.run(View.java:23647) 
        at android.os.Handler.handleCallback(Handler.java:751) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:154) 
        at android.app.ActivityThread.main(ActivityThread.java:6682) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410) 
     Caused by: java.lang.ClassCastException: android.support.v7.widget.GridLayout cannot be cast to android.widget.GridLayout
        at com.example.akash.tikataktoe.MainActivity.playAgain(MainActivity.java:110)
        at java.lang.reflect.Method.invoke(Native Method) 
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385) 
        at android.view.View.performClick(View.java:6199) 
        at android.widget.TextView.performClick(TextView.java:11090) 
        at android.view.View$PerformClick.run(View.java:23647) 
        at android.os.Handler.handleCallback(Handler.java:751) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:154) 
        at android.app.ActivityThread.main(ActivityThread.java:6682) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410) 

Answer 1

那條線在這里：

java.lang.ClassCastException: android.support.v7.widget.GridLayout cannot be cast to android.widget.GridLayout at com.example.akash.tikataktoe.MainActivity.playAgain(MainActivity.java:110)

指出問題的根源。 您正在執行“不良”演員表轉換，因此必須確保使用正確的類！