Question

我有两个类（MainActivity＆amp; Dialogs）我试图将Dialogs类（作为上下文）称为MainAcitivity;

我试过了

        Dialogs WorkOnDialog = (Dialogs)context;
        WorkOnDialog.WorkOnSavedDialog();

这是我的MainAcitivty

public class MainActivity extends AppCompatActivity {



    Context context = this;
    boolean WorkOn = false;
    boolean WorkOff = false;
    Dialogs WorkOnSaveDialog;
//    Dialogs WorkOnSaveDialog = (Dialogs) context;
//    Dialogs WorkOffSaveDialog = (Dialogs)context;




    @Override
    public void onCreate(Bundle savedInstanceState) {


        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


    }


    //Press Work On Button
    public void WorkOnClicked(View v) {

        //Creates ImageButton var for ActionListener
        ImageButton WorkOnClicked = (ImageButton) findViewById(R.id.WorkOn);

        WorkOnClicked.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                // Gets & Sets Date, Filename, Data Content
                // Creates Output Stream to save to file

                String nowDate = DateFormat.getDateTimeInstance().format(new Date());

                String filename = "WorkOnFile";
                String string = nowDate + " Work On";
                FileOutputStream outputStream;

                File file = new File(Environment.getDataDirectory(), filename);


                System.out.println("Work On Button CLicked");

                try {
                    outputStream = openFileOutput(filename, Context.MODE_PRIVATE);
                    outputStream.write(string.getBytes());
                    outputStream.close();
                    System.out.println("!Wrote " + string + " !");
                    System.out.println("Wrote at " + file);
                    WorkOn = true;
                } catch (Exception e) {
                    e.printStackTrace();
                }
                Dialogs WorkOnDialog = (Dialogs)context;
                WorkOnDialog.WorkOnSavedDialog();


            }



        });
    }

    //Press WorkOff Button
    public void WorkOffClicked(View v) {

        //Creates ImageButton var for ActionListener

        ImageButton WorkOffClicked = (ImageButton) findViewById(R.id.WorkOff);

        WorkOffClicked.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                // Gets & Sets Date, Filename, Data Content
                // Creates Output Stream to save to file
                String nowDate = DateFormat.getDateTimeInstance().format(new Date());

                String filename = "WorkOffFile";
                String string = nowDate + " Work Off";
                FileOutputStream outputStream;

                File file = new File(Environment.getDataDirectory(), filename);


                System.out.println(" Work Off Button CLicked");

                try {
                    outputStream = openFileOutput(filename, Context.MODE_PRIVATE);
                    outputStream.write(string.getBytes());
                    outputStream.close();
                    System.out.println("!Wrote " + string + " !");
                    System.out.println("Wrote at " + file);
                    WorkOn=false;
                } catch (Exception e) {
                    e.printStackTrace();
                }

//                WorkOffSaveDialog.WorkOffSavedDialog();

            }

        });

这是我的Dialogs类

public class Dialogs extends AppCompatActivity {

public Context context = this;

public void WorkOnSavedDialog() {
    new AlertDialog.Builder(context)
            .setTitle("Work On File Saved")
            .setMessage("[Displaying for Test] Work On File Saved")
            .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    // continue with delete
                }
            })
            .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    // do nothing
                }
            })
            .setIcon(android.R.drawable.ic_dialog_alert)
            .show();
}

public void WorkOffSavedDialog() {
    new AlertDialog.Builder(context)
            .setTitle("Work Off File Saved")
            .setMessage("[Displaying for Test] Work Off File Saved")
            .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    // continue with delete
                }
            })
            .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    // do nothing
                }
            })
            .setIcon(android.R.drawable.ic_dialog_alert)
            .show();
}


}

任何人都可以向我解释为什么我无法称呼这个＆＃34; Dialogs＆＃34;主要方法内的类？我已经搜索过使用上下文调用方法，我找到的所有内容都没有用，究竟出了什么问题，为什么？

Answer 1

您需要为Dialog类创建构造函数并将MainActivity上下文传递给此构造函数：

public class Dialogs extends AppCompatActivity {

public Context context;

public Dialogs(Context context) {
this.context = context;
}

public void WorkOnSavedDialog() {
    new AlertDialog.Builder(context)
            .setTitle("Work On File Saved")
            .setMessage("[Displaying for Test] Work On File Saved")
            .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    // continue with delete
                }
            })
            .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    // do nothing
                }
            })
            .setIcon(android.R.drawable.ic_dialog_alert)
            .show();
}

public void WorkOffSavedDialog() {
    new AlertDialog.Builder(context)
            .setTitle("Work Off File Saved")
            .setMessage("[Displaying for Test] Work Off File Saved")
            .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    // continue with delete
                }
            })
            .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    // do nothing
                }
            })
            .setIcon(android.R.drawable.ic_dialog_alert)
            .show();
}
}

来自其他类android的类Context

1 个答案: