java - 文本出现在进度条之后 - Android

Question

我正在玩弄 android 中的进度条，并希望我的文本在进度条运行后出现。但我的文字同时出现。明显是放错地方了？但它应该在哪里呢？

package com.example.bmi;

import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;

public class MainActivity extends Activity {
    private ProgressBar progressBar;
    private int progressStatus = 0;
    private Handler handler = new Handler ();
    //private TextView textView;

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


    }


    public void calculateClickHandler(View view) {

        if (view.getId() == R.id.button1) {

            progressBar = (ProgressBar) findViewById(R.id.progressBar1);
            //textView = (TextView) findViewById(R.id.textView1);
              // Start long running operation in a background thread
              new Thread(new Runnable() {
                 public void run() {
                    while (progressStatus < 100) {
                       progressStatus += 1;
                            // Update the progress bar and display the 
                            //current value in the text view
                            handler.post(new Runnable() {


                                        public void run() {
                                           progressBar.setProgress(progressStatus);
                                           //textView.setText(progressStatus+"/"+progressBar.getMax());
                                        }
                            });



                              try {
                                // Sleep for 200 milliseconds. 
                                //Just to display the progress slowly
                                Thread.sleep(50);
                              } catch (InterruptedException e) {
                                  e.printStackTrace();
                                }
                 }


              }
           }).start();

              EditText weightText = (EditText) findViewById(R.id.editText1);
                EditText heightText = (EditText) findViewById(R.id.editText2);
                TextView result = (TextView) findViewById(R.id.textView4);

                float weight = Float.parseFloat(weightText.getText().toString());
                float height = Float.parseFloat(heightText.getText().toString());

                float bmi = calcBMI(weight, height);
                float roundedbmi = (float) (Math.round(bmi*100.0)/100.0);

                String yoFat = fat(roundedbmi);

                result.setText("Your BMI is: " + roundedbmi + "\n" + yoFat); 


        }

    }


    private float calcBMI(float weight, float height) {
        // TODO Auto-generated method stub
        return (float) (weight / (height * height));
    }


    private String fat (float bmi) {
        if (bmi < 16) {
            return "Yo Skinny ass needs some cake!";
        }
        else if (bmi < 18.5) {
            return "Stop eating them salads!";
        }
        else if (bmi < 25) {
            return "Grrrr, Just the way I like it!";
        }
        else if (bmi < 30) {
            return "Put down that cupcake!";
        }
        else {
            return "Ohh you Fat, You love the cake!";
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

Answer 1

实例化线程正下方的代码在执行之前不会等待线程完成其可运行状态。

相反，在新线程的可运行末尾重新进入 UI 线程并设置文本:

    new Thread(new Runnable() {
        @Override
        public void run() {
            while (progressStatus < 100) {
                // Progress update...
            }

            // Progress finished, re-enter UI thread and set text
            handler.post(new Runnable() {
                @Override
                public void run() {
                    EditText weightText = (EditText) findViewById(R.id.editText1);
                    EditText heightText = (EditText) findViewById(R.id.editText2);
                    TextView result = (TextView) findViewById(R.id.textView4);

                    float weight = Float.parseFloat(weightText.getText().toString());
                    float height = Float.parseFloat(heightText.getText().toString());

                    float bmi = calcBMI(weight, height);
                    float roundedbmi = (float) (Math.round(bmi*100.0)/100.0);

                    String yoFat = fat(roundedbmi);

                    result.setText("Your BMI is: " + roundedbmi + "\n" + yoFat);
                }
            });
        }
    }).start();