在意图服务和类之间未传递值

Question

Explanation: I made this intent service in a new class (connectionchecker.java) which is used to check for internet connection. Now in my main class (First.java), the values are not recieved because the if() is never executed. My app doesn't crash , the problem is the TextView is stuck on "CONNECTION:" instead of saying "CONNECTION:You are not connected to the internet." or ""CONNECTION:You are not connected to the internet.".

Code: First.java

 package com.lofty.lofti; import com.lofty.lofti.util.SystemUiHider; import android.annotation.TargetApi; import android.app.Activity; import android.app.SearchManager; import android.content.Context; import android.content.Intent; import android.inputmethodservice.Keyboard; import android.inputmethodservice.KeyboardView.OnKeyboardActionListener; import android.view.KeyEvent; import android.view.View.OnKeyListener; import android.inputmethodservice.KeyboardView; import android.net.Uri; import android.os.Build; import android.os.Bundle; import android.os.Handler; import android.view.MotionEvent; import android.view.View; import android.widget.EditText; import android.widget.ImageView; import android.widget.TextView; import android.widget.Toast; import android.content.BroadcastReceiver; /** * An example full-screen activity that shows and hides the system UI (ie * status bar and navigation/system bar) with user interaction. * * @see SystemUiHider */ public class First extends Activity { /** * Whether or not the system UI should be auto-hidden after * {@link #AUTO_HIDE_DELAY_MILLIS} milliseconds. */ private static final boolean AUTO_HIDE = true; /** * If {@link #AUTO_HIDE} is set, the number of milliseconds to wait after * user interaction before hiding the system UI. */ private static final int AUTO_HIDE_DELAY_MILLIS = 3000; /** * If set, will toggle the system UI visibility upon interaction. Otherwise, * will show the system UI visibility upon interaction. */ private static final boolean TOGGLE_ON_CLICK = true; /** * The flags to pass to {@link SystemUiHider#getInstance}. */ private static final int HIDER_FLAGS = SystemUiHider.FLAG_HIDE_NAVIGATION; /** * The instance of the {@link SystemUiHider} for this activity. */ private SystemUiHider mSystemUiHider; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); getActionBar().hide(); // HIDE ACTION BAR. setContentView(R.layout.activity_first); EditText enter = (EditText) findViewById(R.id.searchbox); enter.setOnKeyListener(new OnKeyListener() { @Override public boolean onKey(View v, int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_ENTER) { EditText searchbox = (EditText) findViewById(R.id.searchbox); String search = searchbox.getText().toString(); Intent open = new Intent(Intent.ACTION_WEB_SEARCH); open.putExtra(SearchManager.QUERY, search); startActivity(open); return true; } else { return false; } } }); } public class Connection extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { Integer connectionn = intent.getIntExtra("connection",0); TextView connectiontext = (TextView) findViewById(R.id.connectiontext); if(connectionn==1) { connectiontext.setText("CONNECTION:You are not connected to the internet."); } if(connectionn==0) { connectiontext.setText("CONNECTION:You are not connected to the internet."); } } } public void exit(View view) { finish(); System.exit(0); } public void usernameclick (View view) { EditText searchbox = (EditText) findViewById(R.id.searchbox); String search = searchbox.getText().toString(); Intent open = new Intent(Intent.ACTION_WEB_SEARCH); open.putExtra(SearchManager.QUERY, search); startActivity(open); } } 

connectionchecker.java

 package com.lofty.lofti; import android.app.IntentService; import android.content.Context; import android.content.Intent; import android.net.ConnectivityManager; import android.net.NetworkInfo; import android.widget.EditText; public class connectionchecker extends IntentService { public static final int connection =0; public connectionchecker() { super("connectionchecker"); } @Override protected void onHandleIntent(Intent intent) { ConnectivityManager connectivityManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE); if(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED || connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.CONNECTED|| connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_ETHERNET).getState()== NetworkInfo.State.CONNECTED) { Intent data = new Intent(this, First.class); data.putExtra("connection",1); sendBroadcast(data); } else { Intent data = new Intent(this, First.class); data.putExtra("connection", 0 ); sendBroadcast(data); } } } 

AndroidManifest.xml

 <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.lofty.lofti" > <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name=".First" android:configChanges="orientation|keyboardHidden|screenSize" android:label="@string/app_name" android:theme="@style/FullscreenTheme" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <service android:name=".connectionchecker"/> <receiver android:name=".First$Connection"/> </application> </manifest> 

Thank you and have a good day.

Logcat:

 10-23 16:01:25.765 2175-2175/com.lofty.lofti E/Zygote﹕ MountEmulatedStorage() 10-23 16:01:25.765 2175-2175/com.lofty.lofti E/Zygote﹕ v2 10-23 16:01:25.775 2175-2175/com.lofty.lofti I/SELinux﹕ Function: selinux_compare_spd_ram, SPD-policy is existed. and_ver=SEPF_GT-I9505_5.0.1 ver=27 10-23 16:01:25.775 2175-2175/com.lofty.lofti I/SELinux﹕ Function: selinux_compare_spd_ram , priority [2] , priority version is VE=SEPF_GT-I9505_5.0.1-1_0032 10-23 16:01:25.775 2175-2175/com.lofty.lofti E/SELinux﹕ [DEBUG] get_category: variable seinfo: default sensitivity: NULL, cateogry: NULL 10-23 16:01:25.775 2175-2175/com.lofty.lofti I/art﹕ Late-enabling -Xcheck:jni 10-23 16:01:25.955 2175-2175/com.lofty.lofti D/ResourcesManager﹕ creating new AssetManager and set to /data/app/com.lofty.lofti-2/base.apk 10-23 16:01:26.185 2175-2175/com.lofty.lofti D/AndroidRuntime﹕ Shutting down VM 10-23 16:01:26.195 2175-2175/com.lofty.lofti E/AndroidRuntime﹕ FATAL EXCEPTION: main Process: com.lofty.lofti, PID: 2175 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.lofty.lofti/com.lofty.lofti.First}: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity. at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2693) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2758) at android.app.ActivityThread.access$900(ActivityThread.java:177) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:145) at android.app.ActivityThread.main(ActivityThread.java:5942) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195) Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity. at android.support.v7.app.AppCompatDelegateImplV7.createSubDecor(AppCompatDelegateImplV7.java:309) at android.support.v7.app.AppCompatDelegateImplV7.ensureSubDecor(AppCompatDelegateImplV7.java:278) at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:252) at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:109) at com.lofty.lofti.First.onCreate(First.java:68) at android.app.Activity.performCreate(Activity.java:6289) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2758)            at android.app.ActivityThread.access$900(ActivityThread.java:177)            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448)            at android.os.Handler.dispatchMessage(Handler.java:102)            at android.os.Looper.loop(Looper.java:145)            at android.app.ActivityThread.main(ActivityThread.java:5942)            at java.lang.reflect.Method.invoke(Native Method)            at java.lang.reflect.Method.invoke(Method.java:372)            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400)            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195) 10-23 16:06:26.538 2175-2175/? I/Process﹕ Sending signal. PID: 2175 SIG: 9 

Answer 1

I just update your code, by following the tuto from Lars http://www.vogella.com/tutorials/AndroidBroadcastReceiver/article.html

1. You have to register the broadcast receiver before it can receive anything. Have a look at this question. https://stackoverflow.com/a/4806091/2733216

    IntentFilter filter = new IntentFilter(Connection.ACTION_RESP); registerReceiver(mConnection, filter); 

2. Your service wasn't started (at least in the code you provided)

   in your Activity 'onCreate'

    // Start your Service Intent msgIntent = new Intent(this, ConnectionChecker.class); startService(msgIntent); 

3. You didn't instantiate your BroadCastReceiver

    // Instanciate your BCR mConnection = new Connection(); 

4. Define a message :

    public static final String ACTION_RESP = "intent.action.MESSAGE_PROCESSED"; 

5. Define the message to the Intent

    data.setAction(MainActivity.Connection.ACTION_RESP); 

6. Use Default Intent Constructor for the one that are sent from the Service

    Intent data = new Intent(); 

Then finally, the whole code :

1. Activity

   public class MainActivity extends AppCompatActivity {

    private Connection mConnection; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); EditText enter = (EditText) findViewById(R.id.searchbox); enter.setOnKeyListener(new View.OnKeyListener() { @Override public boolean onKey(View v, int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_ENTER) { EditText searchbox = (EditText) findViewById(R.id.searchbox); String search = searchbox.getText().toString(); Intent open = new Intent(Intent.ACTION_WEB_SEARCH); open.putExtra(SearchManager.QUERY, search); startActivity(open); return true; } else { return false; } } }); // Start your Service Intent msgIntent = new Intent(this, ConnectionChecker.class); startService(msgIntent); // Instanciate BCR mConnection = new Connection(); // Register BCR IntentFilter filter = new IntentFilter(Connection.ACTION_RESP); registerReceiver(mConnection, filter); } public class Connection extends BroadcastReceiver { public static final String ACTION_RESP = "intent.action.MESSAGE_PROCESSED"; @Override public void onReceive(Context context, Intent intent) { Integer connectionn = intent.getIntExtra("connection", 0); TextView connectiontext = (TextView) findViewById(R.id.connectiontext); if (connectionn == 1) connectiontext.setText("CONNECTION:You are not connected to the internet."); else connectiontext.setText("CONNECTION:You are not connected to the internet."); } } public void exit(View view) { finish(); System.exit(0); } public void usernameclick(View view) { EditText searchbox = (EditText) findViewById(R.id.searchbox); String search = searchbox.getText().toString(); Intent open = new Intent(Intent.ACTION_WEB_SEARCH); open.putExtra(SearchManager.QUERY, search); startActivity(open); } 

   }

2. Service

   public class ConnectionChecker extends IntentService { public static final int connection =0;

    public ConnectionChecker() { super("connectionchecker"); } @Override protected void onHandleIntent(Intent intent) { ConnectivityManager connectivityManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE); if(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED || connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.CONNECTED|| connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_ETHERNET).getState()== NetworkInfo.State.CONNECTED) { Intent data = new Intent(); data.setAction(MainActivity.Connection.ACTION_RESP); data.putExtra("connection", 1); sendBroadcast(data); } else { Intent data = new Intent(); data.setAction(MainActivity.Connection.ACTION_RESP); data.putExtra("connection", 0 ); sendBroadcast(data); } } 

   }

Answer 2

the values are not received because the if() is never executed

Pass an action for the Intent , instead of using like this:

Intent data = new Intent(this, First.class);

But, you should:

Intent data = new Intent("ACTION_NAME");

And make sure that you registered that action to manifest:

<receiver android:name=".First$Connection">
    <intent-filter>
        <action android:name="ACTION_NAME" />
    </intent-filter>
</receiver>

the problem is the TextView is stuck

Make an instance variable for connectiontext :

public class First extends Activity {

    ...
    private TextView connectiontext;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_first);
        getActionBar().hide(); // HIDE ACTION BAR.
        connectiontext = (TextView) findViewById(R.id.connectiontext);
        ...
    }
...
}