Question

我正在开发一款Android应用，我已经在菜单中创建了一个项目＆＃39;关于＆＃39;。我想在单击它时，在单独的页面或活动中显示Dev Name，Contact，App version等文本。我不知道如何做到这一点，我正在使用toast消息来显示这些细节。请帮助！

activity_main.xml中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <ImageButton
        android:id="@+id/btnSwitch"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="100dip"
        android:src="@drawable/btn_switch_on"
        android:background="@null"
        android:contentDescription="@null"
         />   

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/text1"
        android:layout_marginTop="10dp"
        android:paddingLeft="10dp"
        android:lines="2"
        android:id="@+id/text2"
        android:clickable="true"
        android:text="wTorch v1.0"
        android:fontFamily="Droid Sans"
        android:autoLink="all"
        android:typeface="serif"
        android:textSize="20sp"
        android:gravity="right"
        android:textAlignment="gravity" />

</RelativeLayout>

MainActivity.java

package com.wtech.wtorch;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.widget.ImageButton;
import android.widget.Toast;
import android.view.Menu;  
import android.view.MenuItem;


    public class MainActivity extends Activity {

    private static final Parameters para = null;

    private static Camera cam = null;

    private static boolean doubleBackToExitPressedOnce = false;

    ImageButton btnSwitch;

    private Camera camera;
    private boolean isFlashOn;
    private boolean hasFlash;
    Parameters params;
    MediaPlayer mp;


    @Override  
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;  
    }  
    @Override  
    public boolean onOptionsItemSelected(MenuItem item) {  
        switch (item.getItemId()) {  
            case R.id.about:  
                Toast.makeText(getApplicationContext()," App Version - 1.0 \n Developer - Mohammad Waris Ansari \n Contact - mohdwaris723@gmail.com",Toast.LENGTH_LONG).show();
            return true;
            default:  
                return super.onOptionsItemSelected(item);  
        }  
    }  


    @Override
    public void onBackPressed() {
        if (doubleBackToExitPressedOnce) {
            super.onBackPressed();
            return;
        }

        this.doubleBackToExitPressedOnce = true;
        Toast.makeText(this, "Press again to exit", Toast.LENGTH_SHORT).show();

        new Handler().postDelayed(new Runnable() {

            @Override
            public void run() {
                doubleBackToExitPressedOnce=false;                       
            }
        }, 2000);
    } 

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btnSwitch = (ImageButton) findViewById(R.id.btnSwitch);    
        hasFlash = getApplicationContext().getPackageManager()
                .hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);

        if (!hasFlash) {
            AlertDialog alert = new AlertDialog.Builder(MainActivity.this)
                    .create();
            alert.setTitle("Error");
            alert.setMessage("Sorry, your device doesn't support flash light!");
            alert.setButton("OK", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    // closing the application
                    finish();
                }
            });
            alert.show();
            return;
        }

        // get the camera
        getCamera();

        // displaying button image
        toggleButtonImage();


        // Switch button click event to toggle flash on/off
        btnSwitch.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                if (isFlashOn) {
                    // turn off flash
                    turnOffFlash();
                } else {
                    // turn on flash
                    turnOnFlash();
                }
            }
        });
    }


    // Get the camera
    private void getCamera() {
        if (camera == null) {
            try {
                camera = Camera.open();
                params = camera.getParameters();
            } catch (RuntimeException e) {
                Log.e("Camera Error. Failed to Open. Error: ", e.getMessage());
            }
        }
    }
 // Turning On flash
    private void turnOnFlash() {
        if (!isFlashOn) {
            if (camera == null || params == null) {
                return;
            }
            params = camera.getParameters();
            params.setFlashMode(Parameters.FLASH_MODE_TORCH);
            camera.setParameters(params);
            camera.startPreview();
            isFlashOn = true;

            // changing button/switch image
            toggleButtonImage();
        }

    }


    // Turning Off flash
    private void turnOffFlash() {
        if (isFlashOn) {
            if (camera == null || params == null) {
                return;
            } 
            params = camera.getParameters();
            params.setFlashMode(Parameters.FLASH_MODE_OFF);
            camera.setParameters(params);
            camera.stopPreview();
            isFlashOn = false;

            // changing button/switch image
            toggleButtonImage();
        }
    }

    /*
     * Toggle switch button images
     * changing image states to on / off
     * */
    private void toggleButtonImage(){
        if(isFlashOn){
            btnSwitch.setImageResource(R.drawable.btn_switch_on);
        }else{
            btnSwitch.setImageResource(R.drawable.btn_switch_off);
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
    }

    @Override
    protected void onPause() {
        super.onPause();
        turnOffFlash();
    }

    @Override
    protected void onRestart() {
        super.onRestart();
    }

    @Override
    protected void onResume() {
        super.onResume();
        if(hasFlash)
            turnOnFlash();
    }

    @Override
    protected void onStart() {
        super.onStart();
        getCamera();
    }

    @Override
    protected void onStop() {
        super.onStop();
        if (camera != null) {
            camera.release();
            camera = null;
        }
    }

}

menu_main.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android" >
<item
android:id="@+id/about"
android:title="About"
android:icon="@drawable/ic_menu_info_details"/>
</menu>

Answer 1

创建第二个活动并在onOptionsItemSelected

中导航到该活动

@Override
    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()) {
            case R.id.about:
                startActivity(new Intent(this, AboutActivity.class));
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

Answer 2

点击按钮可以打开新活动。像这样更新你的onOptionsItemSelected(MenuItem item)：

   @Override  
            public boolean onOptionsItemSelected(MenuItem item) {  
                switch (item.getItemId()) {  
                    case R.id.about:  
                      Intent intent = new Intent(MainActivity.this,NewActivity.class); // code to start new activity instead of showing toast
                      intent.putExtra("version","1.0");                     
                      startActivity(intent);
                    return true;
                    default:  
                        return super.onOptionsItemSelected(item);  
                }  
            }

您可以使用intent.putExtre()将应用版本，开发者和联系人等数据从一个活动发送到另一个活动，并将这些数据显示给新活动。

在NewActivity中，您可以获取来自旧活动的数据，如下所示：

 Intent intent = getIntent();
    String version= intent.getStringExtra("version");

Answer 3

您需要显示自定义对话框提醒。

dialog.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >

<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:textColor="#FFF"
    android:text="Some Text"/>

<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:textColor="#FFF"
    android:text="Some Text"/>

 <Button
    android:id="@+id/declineButton"
    android:layout_width="100px"
    android:layout_height="wrap_content"
    android:text=" OK "
    android:layout_marginTop="5dp"
    android:layout_marginRight="5dp"
    />

</RelativeLayout>

在你的onOptionsItemSelected中，

  @Override  
   public boolean onOptionsItemSelected(MenuItem item) {  
    switch (item.getItemId()) {  
        case R.id.about:  

   // Create custom dialog object
            final Dialog dialog = new Dialog(MainActivity.this);
            // Include dialog.xml file
            dialog.setContentView(R.layout.dialog);
            // Set dialog title
            dialog.setTitle("About");

          dialog.show();

            Button declineButton = (Button) dialog.findViewById(R.id.declineButton);
            // if decline button is clicked, close the custom dialog
            declineButton.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    // Close dialog
                    dialog.dismiss();
                }
            });

          return true;
          default:  
              return super.onOptionsItemSelected(item);  
      }  
     }

Android - 如何在菜单项中添加文本？

3 个答案: