如何计算android中的百分比

您好，在这段代码中，如何计算百分比。在文本框中显示总数、缺席人数、出席人数和百分比。在这篇文章中，如何显示百分比，但是我得到了total、present和increase的值，但是我不知道如何在这段代码中找到百分比

谁能帮帮我吗

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

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)

试着这样,

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

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希望这能帮助您……

无法理解您的QTI想要在编辑文本中显示百分比如何使用当前和总计计算百分比您使用了什么公式来计算百分比？我使用了这个公式（当前/总计）*100为什么在该公式中写入“”