如何在android中計算百分比

Question

嗨在此代碼中如何計算百分比。在edittext框中顯示總數，缺席數，當前數和百分比。在這個如何顯示百分比，但我得到的總和現在和缺席的價值，但我不是沒有如何找到在此代碼的百分比

任何人都可以請幫助我。

的Java

total[j] = (EditText) findViewById(R.id.total); 
      total[j].setVisibility(View.GONE); 
      Present[j] = (EditText) findViewById(R.id.present); 
      Present[j].setVisibility(View.GONE); 
      Absent[j] = (EditText) findViewById(R.id.absent); 
      Absent[j].setVisibility(View.GONE); 
      percentage[j] = (EditText) findViewById(R.id.percentage); 
      percentage[j].setVisibility(View.GONE); 


      float total1 = Float.valueOf(total[j].getText().toString()); 
      float present1 = Float.valueOf(Present[j].getText().toString()); 

      float per = ((present1/total1) * 100); 
      St_AttendDetails p = (St_AttendDetails) i.next(); 

      tr = new TableRow(this); 


      total[j] = new EditText(this); 
      total[j].setKeyListener(null); 
      total[j].setText(p.getTotal()); 
      total[j].setId(p.getId()); 
      total[j].setLayoutParams(new LayoutParams(
        LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)); 
      total[j].setPadding(5, 5, 5, 5); 

      LinearLayout Ll = new LinearLayout(this); 
      LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
        LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT); 
      params.setMargins(5, 2, 2, 2); 

      Ll.addView(total[j], params); 
      tr.addView((View) Ll); 

      Present[j] = new EditText(this); 

      Present[j].setKeyListener(null); 
      Present[j].setText(p.getPresent()); 
      Present[j].setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, 
        LayoutParams.WRAP_CONTENT)); 
      Present[j].setPadding(5, 5, 5, 5); 

      Ll = new LinearLayout(this); 
      params = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, 
        LayoutParams.WRAP_CONTENT); 
      params.setMargins(0, 3, 3, 3); 

      Ll.addView(Present[j], params); 
      tr.addView((View) Ll); 

      Absent[j] = new EditText(this); 
      Absent[j].setKeyListener(null); 
      Absent[j].setText(p.getAbsent()); 
      Absent[j].setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, 
        LayoutParams.WRAP_CONTENT)); 
      Absent[j].setPadding(5, 5, 5, 5); 

      Ll = new LinearLayout(this); 
      params = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, 
        LayoutParams.WRAP_CONTENT); 
      params.setMargins(0, 3, 3, 3); 

      Ll.addView(Absent[j], params); 
      tr.addView((View) Ll); 

      percentage[j] = new EditText(this); 
      percentage[j].setKeyListener(null); 
      //percentage[j].setText(per); 
      percentage[j].setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, 
        LayoutParams.WRAP_CONTENT)); 
      percentage[j].setPadding(5, 5, 5, 5); 

      Ll = new LinearLayout(this); 
      params = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, 
        LayoutParams.WRAP_CONTENT); 
      params.setMargins(0, 3, 3, 3); 

      Ll.addView(percentage[j], params); 
      tr.addView((View) Ll); 
      tl.addView(tr, new TableLayout.LayoutParams(
        LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT)); 

logcat的

11-22 08:28:40.259: E/AndroidRuntime(4969): FATAL EXCEPTION: main 
11-22 08:28:40.259: E/AndroidRuntime(4969): java.lang.NumberFormatException: Invalid float: "" 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at java.lang.StringToReal.invalidReal(StringToReal.java:63) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at java.lang.StringToReal.parseFloat(StringToReal.java:289) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at java.lang.Float.parseFloat(Float.java:300) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at java.lang.Float.valueOf(Float.java:337) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at com.rushda.attendance.Student_Attendance.addData(Student_Attendance.java:252) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at com.rushda.attendance.Student_Attendance$3$1.run(Student_Attendance.java:128) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at android.os.Handler.handleCallback(Handler.java:725) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at android.os.Handler.dispatchMessage(Handler.java:92) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at android.os.Looper.loop(Looper.java:137) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at android.app.ActivityThread.main(ActivityThread.java:5041) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at java.lang.reflect.Method.invokeNative(Native Method) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at java.lang.reflect.Method.invoke(Method.java:511) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
11-22 08:28:40.259: E/AndroidRuntime(4969):  at dalvik.system.NativeStart.main(Native Method) 

Answer 1

嘗試這樣，

float rCtWt = Float.parseFloat(edtRCtWt.getText().toString()); 
float mk = Float.parseFloat(edtMk.getText().toString()); 
String finalRWt = ((rCtWt * mk)/100) + ""; 
tvFinalRWt.setText(finalRWt); 

希望這可以幫助你......