在 onPostExecute() 之后没有开始新的意图

Posted 2023-05-07

【中文标题】在 onPostExecute() 之后没有开始新的意图

【英文标题】：new intent not getting started after onPostExecute()

【发布时间】：2017-08-09 11:25:33

【问题描述】：

这是一个用于执行我的后台活动的 java 文件，在 onPostExecute() 中我添加了一个启动意图，但它不起作用，这个后台类只是一个 java 文件，它不是任何活动的 java 文件

public class background extends AsyncTask<String,Void,String> 

    private ProgressDialog dialog;
    private ConnectivityManager cm;
    String jsonurl, jsonstring;
    mobile_form mform;
    private  Context context;



    background (Context ctx)
        this.context = context.getApplicationContext();
        this.cm = (ConnectivityManager)ctx.getSystemService(Context.CONNECTIVITY_SERVICE);
        this.dialog = new ProgressDialog(ctx);
        mform = new mobile_form();
    

        @Override
        protected void onProgressUpdate(Void... values) 
            super.onProgressUpdate(values);
        

        @Override
        protected void onPostExecute(String result) 
           context.startActivity(new Intent(context, mobile_form.class));
           NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
            boolean isConnected = activeNetwork != null && activeNetwork.isConnectedOrConnecting();
            if (isConnected) 
                if (dialog.isShowing())
                    dialog.dismiss();
            

        

【参考方案1】：

public class background extends AsyncTask<String,Void,String> 

    private ProgressDialog dialog;
    private ConnectivityManager cm;
    String jsonurl, jsonstring;
    mobile_form mform;
    private  Context context;

    public background (Context ctx)
        this.context = ctx;
        this.cm = (ConnectivityManager)ctx.getSystemService(Context.CONNECTIVITY_SERVICE);
        this.dialog = new ProgressDialog(ctx);
        mform = new mobile_form();
    

    //...
    // doInBackground()
    //...

        @Override
        protected void onProgressUpdate(Void... values) 
            super.onProgressUpdate(values);
        

        @Override
        protected void onPostExecute(String result) 
           NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
            boolean isConnected = activeNetwork != null && activeNetwork.isConnectedOrConnecting();
            if (isConnected) 
                if (dialog.isShowing())
                    dialog.dismiss();
            
            context.startActivity(new Intent(context, mobile_form.class));
        

---

要使用这个 AsynkTask：

new background(getApplicationContext()).execute();

【讨论】：

没有改变它仍然显示不幸的是应用程序已停止工作

【参考方案2】：

您可以按照以下方式解决您的问题 公共类背景扩展 AsyncTask

private ProgressDialog dialog;
private ConnectivityManager cm;
String jsonurl, jsonstring;
mobile_form mform;
private  mContext context;

public background (Context ctx)
    this.mContext = ctx;
    this.cm = (ConnectivityManager)ctx.getSystemService(Context.CONNECTIVITY_SERVICE);
    this.dialog = new ProgressDialog(ctx);
    mform = new mobile_form();


//...
// doInBackground()
//...

    @Override
    protected void onProgressUpdate(Void... values) 
        super.onProgressUpdate(values);
    

    @Override
    protected void onPostExecute(String result) 
       NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        boolean isConnected = activeNetwork != null && activeNetwork.isConnectedOrConnecting();
        if (isConnected) 
            if (dialog.isShowing())
                dialog.dismiss();
        
        mContext.startActivity(new Intent(mContext, mobile_form.class));
    

将此后台任务称为

new background(this).execute();