Android 10 Settings应用如何自定义Preference

一、创建一个TestPreference.java类，然后继承Preference，TestPreference类的构造函数中通过setLayoutResource()方法来加载布局，然后重写父类onBindViewHolder()方法,然后通过holder中holder.itemView来访问子View，示例见代码

package com.android.settings.system;

import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;

import android.content.ContentResolver;
import android.content.Context;
import androidx.preference.Preference;
import androidx.preference.PreferenceViewHolder;
import android.provider.Settings;
import android.util.Log;
import android.view.View;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.widget.TextView;
import com.android.settings.R;
public class TestPreferenceextends Preference implements OnSeekBarChangeListener{
   
   private static final String TAG = "WakeupSensitivityPreference";
   private static final boolean DEBUG = true;
   
   public static final String SENSOR_LEVEL_PATH = "/sys/class/input/input1/threshold";
   public static final String SENSOR_VALID_PATH = "/sys/class/input/input1/int2_enable";
   private TextView summary;
   private ContentResolver mResolver;
   private RadioGroup mRadioGroup;
   public static final String SENSOR_LEVEL = "sensor_level";

   public TestPreference(Context context) {
      super(context);
      mResolver = context.getContentResolver();
      setLayoutResource(R.layout.wakeup_test);
   }

   @Override
   public void onBindViewHolder(PreferenceViewHolder holder) {
      super.onBindViewHolder(holder);
      summary = holder.itemView.findViewById(R.id.sensitivity_tv);
      int level = Settings.Global.getInt(mResolver, SENSOR_LEVEL, 2);

      summary.setText(String.valueOf(level));
      mRadioGroup = holder.itemView.findViewById(R.id.rg_wakeup_sensor);
      RadioButton radioButton = (RadioButton) mRadioGroup.getChildAt(level);

      if (radioButton!=null) {
         radioButton.setChecked(true);
      }
      mRadioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener() {
         
         @Override
         public void onCheckedChanged(RadioGroup group, int checkedId) {
            switch (checkedId) {
            case R.id.rb_off:
               Settings.Global.putInt(mResolver, SENSOR_LEVEL, 0);
               summary.setText(String.valueOf(0));
               break;
            case R.id.rb_low:
               Settings.Global.putInt(mResolver, SENSOR_LEVEL, 1);
               summary.setText(String.valueOf(1));
               break;
                case R.id.rb_middle:
                   Settings.Global.putInt(mResolver, SENSOR_LEVEL, 2);
                   summary.setText(String.valueOf(2));
               break;
                case R.id.rb_hight:
                   Settings.Global.putInt(mResolver, SENSOR_LEVEL, 3);
                   summary.setText(String.valueOf(3));
                   break;
            default:
               break;
            }
            setSensorLevel();
         }
      });

   }

   @Override
   public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
      summary.setText(String.valueOf(progress));
   }

   @Override
   public void onStartTrackingTouch(SeekBar seekBar) {
      
   }

   @Override
   public void onStopTrackingTouch(SeekBar seekBar) {
      int progress = seekBar.getProgress();
      Settings.Global.putInt(mResolver, SENSOR_LEVEL, progress);
   }

   private void setSensorLevel() {
      int level =Settings.Global.getInt(mResolver, SENSOR_LEVEL, 2);
      if(DEBUG) Log.i(TAG, "setSensorLevel() level = " + level);
      try {
         Writer levelWriter = new FileWriter(SENSOR_LEVEL_PATH);
         levelWriter.write(String.valueOf(level));
         levelWriter.flush();
         levelWriter.close();
         Writer validWriter = new FileWriter(SENSOR_VALID_PATH);
         if (0 == level){
            validWriter.write(String.valueOf(0));
         }else {
            validWriter.write(String.valueOf(1));
         }
         validWriter.flush();
         validWriter.close();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

2、创建一个wakeup_test.xml布局文件