Question

按下按钮后应用程序崩溃。

下面的

是堆栈跟踪：

tempnam

这是我的活动课程：

FATAL EXCEPTION: FATAL EXCEPTION: main
Process: com.example.btyagi.tipcalculator, PID: 8357
android.content.res.Resources$NotFoundException: String resource ID #0x0
    at android.content.res.Resources.getText(Resources.java:312)
    at android.support.v7.widget.ResourcesWrapper.getText(ResourcesWrapper.java:52)
    at android.widget.TextView.setText(TextView.java:4417)
    at com.example.btyagi.tipcalculator.MainActivity$1.onClick(MainActivity.java:54)
    at android.view.View.performClick(View.java:5198)
    at android.view.View$PerformClick.run(View.java:21147)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:148)
    at android.app.ActivityThread.main(ActivityThread.java:5417)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

XML文件内容：

public class MainActivity extends AppCompatActivity {
    EditText totalBill;
    EditText totalTip;


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


        final EditText checkAmount = (EditText) findViewById(R.id.editText);
        final EditText noOfPeople = (EditText) findViewById(R.id.editText2);
        final EditText tipPercent = (EditText) findViewById(R.id.editText3);

        totalBill = (EditText) findViewById(R.id.editText4);
        totalTip = (EditText) findViewById(R.id.editText5);


        //TextView totalPerPerson = (TextView) findViewById(R.id.textView5);
        //TextView tipPerPerson = (TextView) findViewById(R.id.textView4);


        Button calculateButton = (Button) findViewById(R.id.button);
//        ArrayList<String> list = new ArrayList<String>();
//        ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this,R.layout.support_simple_spinner_dropdown_item,list);


        // try {


        calculateButton.setOnClickListener(new View.OnClickListener() {


            @Override
            public void onClick(View v) {
                try {
                     int amount = Integer.parseInt(checkAmount.getText().toString());
                     int people = Integer.parseInt(noOfPeople.getText().toString());
                     int tip = Integer.parseInt(tipPercent.getText().toString());
                    totalBill.setText(new StringBuilder().append(amount).append(tip / 100 * amount).toString());
                    totalTip.setText(tip / 100 * amount);
                    // totalPerPerson.setText(totalBill.get/people);
                } catch (NumberFormatException ed) {
                    System.out.print("Not a number");
                }
            }
        });
//


    }
}

Answer 1

最终变量只能初始化一次。

更改 totalBill ， totalTip 和 totalPerPerson TextView（实际上xml中有EditText个）转换为类变量，并将amount，people和tip移动到点击监听器。

public class MainActivity extends AppCompatActivity {


   TextView totalBill;
   TextView totalTip;
   TextView totalPerPerson;

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


        TextView checkAmount = (TextView) findViewById(R.id.textView);
        TextView noOfPeople = (TextView) findViewById(R.id.textView2);
        TextView tipPercent = (TextView) findViewById(R.id.textView3);

        totalBill = (TextView) findViewById(R.id.textView7);
        totalTip = (TextView) findViewById(R.id.textView6);
        totalPerPerson = (TextView) findViewById(R.id.textView5);
        TextView tipPerPerson = (TextView) findViewById(R.id.textView4);


        Button calculateButton = (Button) findViewById(R.id.button);

       calculateButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try { 
                   int amount = Integer.parseInt(checkAmount.getText().toString());
                   int people = Integer.parseInt(noOfPeople.getText().toString());
                   int tip = Integer.parseInt(tipPercent.getText().toString());

                    totalBill.setText(new StringBuilder().append(amount).append(tip / 100 * amount).toString());
                    totalTip.setText(String.valueOf(tip / 100 * amount));
                    // totalPerPerson.setText(totalBill.get/people);
                } catch (NumberFormatException ex) {
                  System.out.print("Not a number");
                }
            }
        });

    }
}

Answer 2

这一行

totalTip.setText(tip / 100 * amount);

应该这样说

totalTip.setText(String.valueOf(tip / 100 * amount));

原因是setText(int resId)是错误的方法，并且会抛出你正在获得的Resources$NotFoundException。

按下按钮后，结果不会显示。用于计算提示的Android应用

2 个答案: