java - 不在 Android Studio 中工作的教师应用百分比

Question

我正在尝试向老师(我妈妈)申请计算成绩字母和可能出现的一定错误数量的百分比。当我按下第一个屏幕上的按钮后，应用程序崩溃了。我想知道是否有人可以帮助我。

import android.content.Context;
import android.media.MediaPlayer;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity{

int MaxInt;

private Button button;

private EditText ETmax;

private TextView TV1;
private TextView TV2;
private TextView TV3;
private TextView TV4;
private TextView TV5;
private TextView TV6;
private TextView TV7;
private TextView TV8;
private TextView TV9;
private TextView TV10;
private TextView TV11;
private TextView TV12;
private TextView TV13;
private TextView TV14;
private TextView TV15;
private TextView TV16;
private TextView TV17;
private TextView TV18;
private TextView TV19;
private TextView TV20;
private TextView TV21;
private TextView TV22;
private TextView TV23;
private TextView TV24;

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

    ETmax = (EditText) findViewById(R.id.editText);

    TV1 = (TextView) findViewById(R.id.textView);
    TV2 = (TextView) findViewById(R.id.textView2);
    TV3 = (TextView) findViewById(R.id.textView3);
    TV4 = (TextView) findViewById(R.id.textView4);
    TV5 = (TextView) findViewById(R.id.textView5);
    TV6 = (TextView) findViewById(R.id.textView6);
    TV7 = (TextView) findViewById(R.id.textView7);
    TV8 = (TextView) findViewById(R.id.textView8);
    TV9 = (TextView) findViewById(R.id.textView9);
    TV10 = (TextView) findViewById(R.id.textView10);
    TV11 = (TextView) findViewById(R.id.textView11);
    TV12 = (TextView) findViewById(R.id.textView12);
    TV13 = (TextView) findViewById(R.id.textView13);
    TV14 = (TextView) findViewById(R.id.textView14);
    TV15 = (TextView) findViewById(R.id.textView15);
    TV16 = (TextView) findViewById(R.id.textView16);
    TV17 = (TextView) findViewById(R.id.textView17);
    TV18 = (TextView) findViewById(R.id.textView18);
    TV19 = (TextView) findViewById(R.id.textView19);
    TV20 = (TextView) findViewById(R.id.textView20);
    TV21 = (TextView) findViewById(R.id.textView21);
    TV22 = (TextView) findViewById(R.id.textView22);
    TV23 = (TextView) findViewById(R.id.textView23);
    TV24 = (TextView) findViewById(R.id.textView24);

    //TV1-8 how many wrong
    //TV9-16 percentage
    //TV17-24 letter grade

    button = (Button) findViewById(R.id.button);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
           MaxInt = Integer.parseInt(ETmax.getText().toString());
            setContentView(R.layout.activity_main);
            TV1.setText(MaxInt - 1);
            TV2.setText(MaxInt - 2);
            TV3.setText(MaxInt - 3);
            TV4.setText(MaxInt - 4);
            TV5.setText(MaxInt - 5);
            TV6.setText(MaxInt - 6);
            TV7.setText(MaxInt - 7);
            TV8.setText(MaxInt - 8);
            TV9.setText((int) Math.round((MaxInt - 1) / MaxInt) + "%");
            TV10.setText((int) Math.round((MaxInt - 2) / MaxInt) + "%");
            TV11.setText((int) Math.round((MaxInt - 3) / MaxInt) + "%");
            TV12.setText((int) Math.round((MaxInt - 4) / MaxInt) + "%");
            TV13.setText((int) Math.round((MaxInt - 5) / MaxInt) + "%");
            TV14.setText((int) Math.round((MaxInt - 6) / MaxInt) + "%");
            TV15.setText((int) Math.round((MaxInt - 7) / MaxInt) + "%");
            TV16.setText((int) Math.round((MaxInt - 8) / MaxInt) + "%");


        }
    });

}

}

Answer 1

从 public void onClick 中删除此行

setContentView(R.layout.activity_main);

如果您只想更新 TextView 中显示的文本，那么它看起来应该适合您。如果有任何预期的布局更改，您将必须启动新的 Activity 或 fragment 。