Question

我有一个名为getCustomAddress()的方法应该显示AlertDialog，并保存用户输入的地址。此方法似乎在方法getTransportType()和getGoogleDirections之后执行。我希望getCustomAddress执行并在这些其他方法之前显示AlertDialog。

我使用调试器逐步完成了这些方法。＃2中的if语句确实根据调试器评估为true（当我选择＆＃34; Custom＆＃34;来自微调器/下拉列表时）。

launchMapButton.setOnClickListener(new Button.OnClickListener() {
        @Override
        public void onClick(View view) {

            //1. Find out where user wants to go
            getDestination(addressFieldSpinner);

            //2. Check for custom address
            if (address.equals("Custom")) {
                getCustomAddress();
            }

            //3. Find out what transportation method user wants
            GetTransportType(googTransitButton, googBikeButton, googDrivingButton, googWalkingButton);

            //4. Get directions from Google Maps
            getGoogleDirections(mode);

        }
    });

以下是整个MainActivity.java文件：

public class MainActivity extends Activity {
    private String friendlyLocation = "";
    private String address = "";
    private String mode = "@mode=d";  //mode b is bicycling, mode d is for driving, mode t is for transit, mode w is for walking

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

        final Spinner addressFieldSpinner = (Spinner) findViewById(R.id.dropdownEditText);
        final Button launchMapButton = (Button) findViewById(R.id.launchMapButton);
        final RadioButton googTransitButton = (RadioButton) findViewById(R.id.googTransitButton);
        final RadioButton googBikeButton = (RadioButton) findViewById(R.id.googBicycleButton);
        final RadioButton googDrivingButton = (RadioButton) findViewById(R.id.googDrivingButton);
        final RadioButton googWalkingButton = (RadioButton) findViewById(R.id.googWalkButton);
        final Button exitButton = (Button)findViewById(R.id.exit_button);


        // Create an ArrayAdapter using the string array and a default spinner layout
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
                R.array.locations_array, android.R.layout.simple_spinner_item);
        // Specify the layout to use when the list of choices appears
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        // Apply the adapter to the spinner
        addressFieldSpinner.setAdapter(adapter);

        launchMapButton.setOnClickListener(new Button.OnClickListener() {
            @Override
            public void onClick(View view) {

                //1. Find out where user wants to go
                getDestination(addressFieldSpinner);

                //2. Check for custom address
                if (address.equals("Custom")){
                    getCustomAddress();
                }

                    //3. Find out what transportation method user wants
                    GetTransportType(googTransitButton, googBikeButton, googDrivingButton, googWalkingButton);

                    //4. Get directions from Google Maps
                    getGoogleDirections(mode);

            }
        });

        View.OnClickListener exit = new View.OnClickListener(){
            @Override
            public void onClick(View view) {
                finish();
            }
        };

        exitButton.setOnClickListener(exit);
    }

    private void getDestination(Spinner addressFieldSpinner) {
        friendlyLocation = addressFieldSpinner.getSelectedItem().toString();

        if (friendlyLocation.equals("Home")) {
            address = getString(R.string.homeAddress);
        } else if (friendlyLocation.equals("Sarahs house")) {
            address = getString(R.string.SarahsAddress);
        } else if (friendlyLocation.equals("Work")) {
            address = getString(R.string.workAddress);
        } else if (friendlyLocation.equals("Custom")) {
            address = "Custom";
        } else {
            //do nothing
        }
    }

    private String GetTransportType(RadioButton googTransitButton, RadioButton googBikeButton, RadioButton googDrivingButton, RadioButton
            googWalkingButton) {

        if (googBikeButton.isChecked()){
            mode = "&mode=b";  //user chose biking
        }
        else if (googDrivingButton.isChecked()){
            mode = "&mode=d"; //user choose driving
        }
        else if (googTransitButton.isChecked()) {
            mode = "&mode=transit";  //user chose public transit
        }
        else if (googWalkingButton.isChecked()){
            mode = "&mode=w"; //user chose walking
        }
        return mode;
    }

    private void getGoogleDirections(String mode) {
        boolean connected = isConnected();

        if (!connected){
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setTitle("Mappy is sorry...")
                    .setIcon(R.mipmap.ic_launcher)
                    .setMessage("You do not have a mobile or wifi connection with internet service at this time.")
                    .setCancelable(false)
                    .setNegativeButton("OK",new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int id) {
                            dialog.cancel();
                        }
                    });
            AlertDialog alert = builder.create();
            alert.show();
        }

        else if (address == null || address == "") {
            Toast.makeText(MainActivity.this, "It looks like you select custom address, but did not enter an address.", Toast.LENGTH_LONG).show();
        }

        else {
            try {
                address = address.replace(' ', '+');
                Uri mapsIntentUri = Uri.parse("google.navigation:q=" + address + mode);
                Intent mapIntent = new Intent(Intent.ACTION_VIEW, mapsIntentUri);
                mapIntent.setPackage("com.google.android.apps.maps");
                startActivity(mapIntent);
            }
            catch (Exception exception) {
            }
        }
    }

    public class SpinnerActivity extends Activity implements AdapterView.OnItemSelectedListener {

        public void onItemSelected(AdapterView<?> parent, View view,int pos, long id) {

            friendlyLocation = parent.getItemAtPosition(pos).toString();

          /*  if (friendlyLocation.equals("Home")) {
                address = "2617 SE 35th Place";
            } else if (friendlyLocation.equals("Sarahs house")) {
                address = "3946 NE Failing, Portland, OR 97212";
            } else if (friendlyLocation.equals("Work")) {
                address = "619 SW 11th Avenue, Portland, OR 97205";
            } else if (friendlyLocation.equals("Custom")) {
                address = getCustomAddress();
            } else {
            }*/
        }

        public void onNothingSelected(AdapterView<?> parent) {
            // Another interface callback

        }
    }

    private String getCustomAddress() {
        final EditText addressEditText = new EditText(this);
        final String[] customAddress = {""};

        AlertDialog.Builder alertDialog = new AlertDialog.Builder(this);
        alertDialog.setTitle("Please enter destination address");
        alertDialog.setView(addressEditText);
        alertDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int whichButton){
                customAddress[0] =  addressEditText.getText().toString();
            }
        });
        alertDialog.setNegativeButton("CANCEL", null);
        alertDialog.create().show();

        return customAddress[0];
    }

    //Checks for mobile or wifi connectivity, returns true for connected, false otherwise
    private boolean isConnected() {
        ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        return connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED ||
                connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.CONNECTED;
    }

}

Answer 1

是。它无序，因为无论getCustomAddress仍然显示，方法AlertDialog都已完成。当您看到对话框时，表示alertDialog.create().show();已完成，然后从getCustomAddress返回以执行下一行GetTransportType。一个简单的解决方法是：

private String getCustomAddress() {
    final EditText addressEditText = new EditText(this);
    final String[] customAddress = {""};

    AlertDialog.Builder alertDialog = new AlertDialog.Builder(this);
    alertDialog.setTitle("Please enter destination address");
    alertDialog.setView(addressEditText);
    alertDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int whichButton){
            customAddress[0] =  addressEditText.getText().toString();
            //add call to ggtransporttype here********
            doNext();//or you can use a handler here!!
    });
    alertDialog.setNegativeButton("CANCEL", null);
    alertDialog.create().show();

    return customAddress[0];
}


 private void doNext(){
       //3. Find out what transportation method user wants
        GetTransportType(googTransitButton, googBikeButton, googDrivingButton, googWalkingButton);

        //4. Get directions from Google Maps
        getGoogleDirections(mode);

  }

Answer 2

通过在调用任何方法之前创建对话框然后随时显示，可以解决此问题的一种方法。首先在MainActivity中声明一个成员：

private AlertDialog.Builder alertDialog;

然后在你的MainActivity's onCreate()中你可以创建（不显示）对话框：

final String[] customAddress = {""};
 final EditText addressEditText = new EditText(this);
 alertDialog = new AlertDialog.Builder(this);
        alertDialog.setTitle("Please enter destination address");
        alertDialog.setView(addressEditText);
        alertDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int whichButton){
                customAddress[0] =  addressEditText.getText().toString();
            }
        });
        alertDialog.setNegativeButton("CANCEL", null);
        alertDialog.create();

您甚至可以使用不同的代码模块化方法提取用于创建对话框的代码。现在，您可以在调用其他方法之前显示该对话框：

launchMapButton.setOnClickListener(new Button.OnClickListener() {
            @Override
            public void onClick(View view) {

                //1. Find out where user wants to go
                getDestination(addressFieldSpinner);

                //2. Check for custom address
                if (address.equals("Custom")){
                    alertDialog.show();
                }

                    //3. Find out what transportation method user wants
                    GetTransportType(googTransitButton, googBikeButton, googDrivingButton, googWalkingButton);

                    //4. Get directions from Google Maps
                    getGoogleDirections(mode);

            }
        });

显示AlertDialog似乎无序执行的方法

2 个答案: