Shulou(Shulou.com)06/02 Report--

Editor to share with you Andriod how to achieve automatic switch, I believe that most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to understand it!

First, look at a quote:

ARemoteViews object (and, consequently, an App Widget) can support thefollowing layout classes:*FrameLayout*LinearLayout*RelativeLayoutAndthe following widget classes:*AnalogClock*Button*Chronometer*ImageButton*ImageView*ProgressBar*TextViewDescendantsof these classes are not supported.

It can be seen that there are only seven controls that can be used in our widget: AnalogClock,Button,Chronometer,ImageButton,mageView,ProgressBar,TextView, while these commonly used controls such as Listview,Editview,Scrollview cannot be used in our Widget. In fact, the source code of all these controls is placed in:

Framework/base/core/java/android/widget

Under this directory, the seven controls are available because of the @ RemoteView tag, so we can take a look at the source code:

AnalogClock.java:39:@RemoteView AnalogClock.java-40-publicclass AnalogClock extends View {ImageButton.java:66:@RemoteView ImageButton.java-67-publicclass ImageButton extends ImageView {… ..

So if we want to use controls like Listview in widget, we need to write a class exactly like Listview, tag it with @ RemoteView, and copy it to the framework/base/core/java/android/widget directory.

Then we can use the control we wrote in Widget, because it has the same @ RemoteView tag as any other available control, so it can be recognized by the RemoteView object.

Now that we know the principle, we can follow these steps (take my custom AnalogClock as an example):

1. First of all, I completely copied the AnalogClock.java in the source code named MyClock.java to the framework/base/core/java/android/widget directory, and then modified the code according to my own requirements.

two。 The resource files used by this MyClock.java must be stored in the frameworks/base/core/res/res directory. And it must be quoted in this way: com.android.internal.R.drawable.*

However, if you do this, it is not convenient to change resources. We know that every system control has a style file, so what I do is:

First, look at the style source file of the system's AnalogClock.java:

Frameworks/base/core/res/res/values/attrs.xmlprivate Drawable mMinuteHand; public MyClock (Context context, AttributeSet attrs, intdefStyle) {super (context,attrs, defStyle); Resources r = context.getResources (); TypedArray a = context.obtainStyledAttributes (attrs,com.android.internal.R.styleable.AnalogClock,defStyle,0); mMinuteHand = a.getDrawable (com.android.internal.R.styleable.AnalogClock_hand_minute) / / here is the call to the parameter if (mMinuteHand== null) {mMinuteHand= r.getDrawable (com.android.internal.R.drawable.clock_hand_minute) in attrs.xml; / / and here is the call to the resource in the system's frameworks/base/core/res/res directory}}

I define it myself in the layout configuration file of widget:

Xmlns:android= "http://schemas.android.com/apk/res/android" android:id=" @ + id/rl_widget_clockView "android:hand_minute=" @ drawable/minute_white "/ / this is the reference to the resource android:layout_width=" 80dp "android:layout_height=" 80dp "/ > under the local drawable.

3. By this time, most of the work is basically done, and we need to compile the entire SDK. But note that I have a variety of compilation errors in the compilation process, and the prompts are all unknown, which is very confusing, and finally I come up with a set of compilation methods with a very high success rate.

First compile the entire pure source code in the root directory make-j4 (be careful not to add any of our own defined classes and resources), and then copy our custom classes and resources to framework after about 1-2 hours of successful compilation, and then compile again in the root directory make-j4.

If we want to test the code we added, we need to execute the emulator command to start a newly compiled simulator after all has been compiled, and then install our APK on it.

The above is all the contents of the article "how to switch on and off automatically in Andriod". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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