Android advanced components ----- progress bar, Android ----- progress bar

Android advanced components ----- progress bar, Android ----- progress bar

The progress bar component is one of the important Android components. When a program is executed in the background, the foreground progress bar displays the percentage of the program execution progress dynamically. It is a time-consuming program that allows users to feel in their control and improve program-friendly.

Android supports several styles of progress bars. You can set the progress bar style through the style attribute, which is as follows:

@ Android: style/Widget. ProgressBar. Horizontal progress bar

@ Android: style/Widget. ProgressBar. Inverse General ring progress bar

@ Android: style/Widget. ProgressBar. Large ring progress bar

@ Android: style/Widget. ProgressBar. Large. Inverse Large ring progress bar

@ Android: style/Widget. ProgressBar. Small ring progress bar

@ Android: style/Widget. ProgressBar. Small. Inverse Small ring progress bar

In addition, the progress bar also has the following attributes in the xml file:

Android: max sets the maximum value of the progress bar

Android: rpogress specifies the progress value of the progress bar that has been completed

Android: ProgressDrawable

The progress bar component has two most common methods: setProgress () to set the progress of the progress bar that has been completed; incrementProgressBy () to set the progress bar to increase or decrease; the parameter is increased when a positive number increases, and the negative number decreases;

Instance operation: The following shows the progress bar and the ring progress bar.

1. Create a project, add two progress bars to the layout, one being a ring and the other being a horizontal progress bar.

            <ProgressBar            android:id="@+id/progressBar1"            style="?android:attr/progressBarStyleHorizontal"            android:layout_gravity="center_horizontal"            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:max="100"            android:layout_weight="1" />        <ProgressBar            android:id="@+id/progressBar2"            style="?android:attr/progressBarStyleSmall"            android:layout_gravity="center_horizontal"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_weight="1" />

2. Get the progress bar in the main activity and define a progress variable and a Handler object for message processing.

Hp = (ProgressBar) findViewById (R. id. progressBar1); cp = (ProgressBar) findViewById (R. id. progressBar2); h = new Handler () {@ Override public void handleMessage (Message msg) {if (msg. what = 0x11) {hp. setProgress (progress);} else {Toast. makeText (MainActivity. this, "time-consuming completion", Toast. LENGTH_SHORT ). show ();} hp. setVisibility (View. GONE); cp. setVisibility (View. GONE );}};

3. Use an anonymous internal class to instantiate a message to process the Handler class object, and override the handlerMessage () method. The update progress is displayed when the time consumption is not completed.

H = new Handler () {public void handleMessage (Message msg) {if (msg. what = 0x11) {hp. setProgress (progress);} else {Toast. makeText (MainActivity. this, "time-consuming completion", Toast. LENGTH_SHORT ). show ();} hp. setVisibility (View. GONE); cp. setVisibility (View. GONE );}}

4. When thread time is enabled, sendMessage () sends and processes messages.

        new Thread(new Runnable() {                        @Override            public void run() {                while(true){                    progress = doWork();                    Message m = new Message();                    if(progress <= 100){                        m.what = 0x11;                        h.sendMessage(m);                    }else {                        m.what = 0x10;                        h.sendMessage(m);                        break;                    }                }                            }                        private int doWork(){                progress += Math.random()*10;                try {                    Thread.sleep(2000);                } catch (InterruptedException e) {                    e.printStackTrace();                }                return progress;            }        }).start();

Run the code to view the ring progress bar and horizontal progress bar update.