In-depth explanation of SeekBar (slider) in Android basics.

2 years ago
William Carter
2 minutes

A SeekBar is a commonly used user interface component in Android that allows users to adjust the size of a value by dragging their finger. SeekBar is typically used for scenarios like adjusting volume and displaying progress bars.

The steps for using SeekBar are as follows:

  1. Add a SeekBar control in the XML layout file.
<SeekBar
    android:id="@+id/seekBar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />
  1. Retrieve an instance of the SeekBar control in Java code and configure a listener:
SeekBar seekBar = findViewById(R.id.seekBar);
seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
    @Override
    public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
        // 当SeekBar的进度改变时调用，参数progress表示当前进度值
        // 如果是用户拖动导致的进度改变，则fromUser为true，否则为false
    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
        // 当用户开始拖动SeekBar时调用
    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        // 当用户停止拖动SeekBar时调用
    }
});
  1. Handle the progress change event of the SeekBar in the listener’s callback method.

Some common properties and methods of the SeekBar are as follows:

  1. android:max: Set the maximum value of the SeekBar.
  2. Set the current progress value of the SeekBar using setProgress(int progress).
  3. Retrieve the current progress value of the SeekBar by calling getProgress().
  4. addListener to SeekBar.

Important points to note:

  1. You can customize the style of the SeekBar according to your needs by changing properties such as the background and slider.
  2. In the callback method of the listener, relevant business logic can be executed as needed, such as updating the UI display of a progress bar or adjusting the volume.
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