不適用於Android Studio的教師的百分比應用

Question

我想爲老師（我的媽媽）提供一個應用程序來計算等級字母和一定數量的可能數量錯誤的百分比。按下第一個屏幕上的按鈕後，應用程序崩潰。我想知道是否有人可以幫助我。

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

刪除此行從公共無效的onClick

setContentView(R.layout.activity_main); 

，它看起來像它應該爲你工作，如果你想要做的一切都更新文本視圖中顯示的文本。如果有任何預期的佈局更改，您將不得不開始新的活動或片段。

Answer 2

你不能調用的setContentView按鈕被點擊時改變佈局。如果您想更改顯示內容，則需要手動設置視圖可見/不可見，使用ViewFlipper，在您的活動容器中加載新的片段或加載新的活動。從您的代碼看來，您可能想要使用main_activity佈局啓動一個新的Activity。

Answer 3

使用這個，如果你想開始一個新的活動

Intent intent=new Intent(MainActivity.this, the_name_of_class_to_go.class); 
startActivity(intent);