无法setPositiveButton

Question

如果GPS关闭，我想在启动器活动之前启动应用程序时显示带有“ENABLE GPS”和“CANCEL”两个按钮的对话框，否则如果GPS打开，启动器活动将打开。当用户启动时单击“启用GPS”它将进入GPS设置，当用户单击取消时，我想显示另一个标题为“如何用户应用程序”的对话框，按钮“确定”，当用户点击“确定”时，我希望启动器活动到开了。 为此，我使用以下代码：

    if (!isGPSEnabled) {
        // no GPS provider is enabled
        // Creating the Dialog box
        AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this)
                .create();
        alertDialog.setTitle("Settings");
        alertDialog.setMessage("Enable GPS for accessing the Application");
        alertDialog.setButton("GPS Settings",
                new DialogInterface.OnClickListener() {
                    // creating Button i.e GPS Setting in the Dialog Box
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub

                        startActivity(new Intent(
                                android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS));

                    }
                });
        alertDialog.show();
        // creating Button i.e Cancel in the Dialog Box
        alertDialog.setButton2("Cancel",
                new DialogInterface.OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                        // Creating another Dialog when "Cancel" is pressed
                        AlertDialog whencancelpressed = new AlertDialog.Builder(
                                MainActivity.this).create();
                        whencancelpressed.setTitle("How to use the app");
                        whencancelpressed
                                .setMessage("Enter the contacts to whom you want to send the message.Double tap power button in emergency");
                        whencancelpressed.setButton("Ok",
                                new DialogInterface.OnClickListener() {
                                    @Override
                                    public void onClick(
                                            DialogInterface dialog,
                                            int which) {
                                        // TODO Auto-generated method stub
                                        Intent pressedokay = new Intent(
                                                getApplicationContext(),
                                                MainActivity.class);
                                        startActivity(pressedokay);
                                    }
                                });
                        whencancelpressed.show();
                    }
                });

    } else {
        // GPS provider is enabled
    }

我面临的问题是，我无法进行“取消”按钮显示，当经过几个教程后，我试图将setButton更改为setPositiveButton，eclipse显示错误。

Answer 1

此代码100％正常工作，只是随心所欲。所有这些都将c作为上下文传递。 在您的活动中声明此内容并使用您的活动名称替换活动名称：

Context c = ActivityName.this;

  AlertDialog.Builder builder = new AlertDialog.Builder(c);

            builder.setTitle(R.string.confirm);
            builder.setMessage(R.string.deleteConfirm);

            builder.setPositiveButton(R.string.deleteBtnTxt,

            new DialogInterface.OnClickListener() {

                public void onClick(DialogInterface dialog, int which) {
                      startActivity(new Intent(
                            android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS));

                    dialog.dismiss();
                }

            });

            builder.setNegativeButton(R.string.no,
                    new DialogInterface.OnClickListener() {

                        @Override
                        public void onClick(DialogInterface dialog,
                                int which) {
                            dialog.dismiss();
                        }
                    });

            AlertDialog alert = builder.create();
            alert.show();

Answer 2

尝试在显示Dialog之前设置取消按钮，如下所示：

    if (!isGPSEnabled) {
            // no GPS provider is enabled
            // Creating the Dialog box
            AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this)
                    .create();
            alertDialog.setTitle("Settings");
            alertDialog.setMessage("Enable GPS for accessing the Application");
            alertDialog.setPositiveButton("GPS Settings",
                    new DialogInterface.OnClickListener() {
                        // creating Button i.e GPS Setting in the Dialog Box
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            // TODO Auto-generated method stub

                            startActivity(new Intent(
                                    android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS));

                        }
                    });
// creating Button i.e Cancel in the Dialog Box
    alertDialog.setNegativeButton("Cancel",
                    new DialogInterface.OnClickListener() {

                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            // TODO Auto-generated method stub
                            // Creating another Dialog when "Cancel" is pressed
                            AlertDialog whencancelpressed = new AlertDialog.Builder(
                                    MainActivity.this).create();
                            whencancelpressed.setTitle("How to use the app");
                            whencancelpressed
                                    .setMessage("Enter the contacts to whom you want to send the message.Double tap power button in emergency");
                            whencancelpressed.setButton("Ok",
                                    new DialogInterface.OnClickListener() {
                                        @Override
                                        public void onClick(
                                                DialogInterface dialog,
                                                int which) {
                                            // TODO Auto-generated method stub
                                            Intent pressedokay = new Intent(
                                                    getApplicationContext(),
                                                    MainActivity.class);
                                            startActivity(pressedokay);
                                        }
                                    });
                            whencancelpressed.show();
                        }
                    });
            alertDialog.show();



        } else {
            // GPS provider is enabled
        }