Android点击button弹出ProgressDialog，响应结束后ProgressDialog消失

港控/mmm° 2022-11-04 05:52 192阅读 0赞

使用背景：项目中需要使用几个机器学习模型，由于加载很缓慢，所以考虑用ProgressDialog来进行提示，预测结束后dialog自动消失。  
  效果如下：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0N5cmlsX0tJ_size_16_color_FFFFFF_t_70_pic_center]

## 1.声明Handler和ProgressDialog ##

public ProgressDialog progressDialog;
    public Handler handler = null;

## 2.点击事件 ##

query.setOnClickListener(v -> { 
        progressDialog = new ProgressDialog(AdaBoostActivity.this);
        progressDialog.setTitle("提示");
        progressDialog.setMessage("正在加载...");
        progressDialog.setIcon(R.drawable.running);
        new Thread(){ 
            public void run(){ 
                try{ 
                    runOnUiThread(() -> createList());
                    Message msg = new Message();
                    msg.what = 1;
                    handler.sendMessage(msg);
                }catch(Exception e){ 
                    e.printStackTrace();
                }
            }
        }.start();//线程启动
        handler = new Handler(){ 
            @Override
            public void handleMessage(@NonNull Message msg) { 
                super.handleMessage(msg);
                progressDialog.dismiss();
                ToastUtil.showMessage(AdaBoostActivity.this, "预测完成!");
            }
        };
        progressDialog.show();
    });

其中：

runOnUiThread(() -> createList());

createList()方法完成后ProgressDialog消失，因为createList()中涉及到渲染TextView，所以使用runOnUiThread()。  
  createList完成后handler发送消息：

Message msg = new Message();
    msg.what = 1;
    handler.sendMessage(msg);

然后销毁dialog：

handler = new Handler(){ 
        @Override
        public void handleMessage(@NonNull Message msg) { 
            super.handleMessage(msg);
            progressDialog.dismiss();
            ToastUtil.showMessage(AdaBoostActivity.this, "预测完成!");
        }
    };

## 3.销毁线程 ##

@Override
    protected void onDestroy() { 
        super.onDestroy();
        if(handler != null) { 
            handler.removeCallbacksAndMessages(null);
        }
    }

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0N5cmlsX0tJ_size_16_color_FFFFFF_t_70_pic_center]: /images/20221023/397aefa183744558aa38e3f1d20e695c.png