Question

我正在制作一个Android应用程序，需要一个按钮来执行两个taks： 1.当用户在EditText中提供错误的输入时，该按钮应在TextView中显示错误消息。

如果用户提供了正确的输入，那么在点击按钮时，它将跳转到另一个活动。

我的应用是一种简单的游戏，包含4项活动（activity_1，activity_2，activity_3，activity_4）。它要求在activity_2中输入。如果输入错误，则会显示错误消息。但是在提供正确的输入时，应用程序崩溃了。

代码activity_2.xml：

<Button
 android:id="@+id/buttonClickMe"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:layout_below="@+id/textView7"
 android:layout_centerHorizontal="true"
 android:layout_marginTop="18dp"
 android:onClick="sendMessage"
 android:text="@string/button_start" />

代码activity_2.java：

final Button buttonStart = (Button) findViewById(R.id.button1)
buttonStart.setOnClickListener(new OnClickListener() {

        public void onClick(View arg0) {

            int no = Integer.valueOf(numberField.getText().toString());

            switch (no)
            {
               case 1 : maxRand = 15;  // the random number will be between 0 and maxRand
               break;
               case 2 : maxRand = 30;
               break;
               case 3 : maxRand = 50;
               break;
               case 4 : maxRand = 100;
               break;
               default : textField.setText("Invalid Argument, Please try again.");
               break;
            }

            if(maxRand != 0){
                randNumber = (int) (Math.random() * maxRand);
                /*textField.setText("Now click Start button !");
                  buttonStart.setVisibility(View.VISIBLE);*/
                startActivity(intent);   //This starts a new activity
            }
        }
    });

以及onClick方法后跟的代码：

public void sendMessage(View view){     //This method is called everytime when the button is clicked

    intent = new Intent(this,ShowResultsActivity.class);
}

我已将意图声明为该类的数据成员。

请帮帮我。并记得提供一堆代码供参考。

Answer 1

尝试在setOnClickListener本身启动Intent

final Button buttonStart =（Button）findViewById（R.id.button1） buttonStart.setOnClickListener（new OnClickListener（）{

    public void onClick(View arg0) {

        int no = Integer.valueOf(numberField.getText().toString());

        switch (no)
        {
           case 1 : maxRand = 15;  // the random number will be between 0 and maxRand
           break;
           case 2 : maxRand = 30;
           break;
           case 3 : maxRand = 50;
           break;
           case 4 : maxRand = 100;
           break;
           default : textField.setText("Invalid Argument, Please try again.");
           break;
        }

        if(maxRand != 0){
            randNumber = (int) (Math.random() * maxRand);
            intent = new Intent(this,ShowResultsActivity.class);
            startActivity(intent);   //This starts a new activity
        }
    }
});

如果不能解决问题。在这里看看你的logcat输出..

Answer 2

public void sendMessage(View view){     
    //This method is called everytime when the button is clicked
    int no = Integer.valueOf(numberField.getText().toString());

            switch (no)
            {
               case 1 : maxRand = 15;  // the random number will be between 0 and maxRand
               break;
               case 2 : maxRand = 30;
               break;
               case 3 : maxRand = 50;
               break;
               case 4 : maxRand = 100;
               break;
               default : 
                   textField.setText("Invalid Argument, Please try again.");
                   // add this to ensure that you won't start activity
                   maxRand = 0;
               break;
            }

            if(maxRand != 0){
                randNumber = (int) (Math.random() * maxRand);
                intent = new Intent(this,ShowResultsActivity.class);
                startActivity(intent);   //This starts a new activity
            } else {
                   // maxRand == 0 ===> ERRORS, update your textField here
                   textField.setText("Invalid Argument, Please try again.");
            }
}

创建一个可以执行多个任务的android按钮

2 个答案: