自定义view(13)自定义属性

1.添加attrs.xml文件

　　在android studio下，在res/values 下新建资源文件attrs.xml

2.添加自定义的属性

在attrs.xml中添加属性，如下。其中format是属性的类型，如float,color,boolean,dimension

 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <declare-styleable name="thermograph">
         <attr name="minValue"       format="float" />
         <attr name="maxValue"       format="float" />
         <attr name="ratio"          format="float" />
         <attr name="hotValue"       format="float" />
         <attr name="coldValue"      format="float" />
         <attr name="thermoValue"    format="float" />
         <attr name="textSize"       format="dimension" />
         <attr name="warningColor"   format="color" />
         <attr name="contourColor"   format="color" />
         <attr name="textColor"      format="color" />
         <attr name="borderColor"    format="color" />
         <attr name="hotColor"       format="color" />
         <attr name="coldColor"      format="color" />
         <attr name="valueColor"     format="color" />
         <attr name="showValue"      format="boolean" />

     </declare-styleable>
 </resources>

3.在布局文件中使用自定义的属性

3.1 在布局文件根结点中添加命名空间。

 <?xml version="1.0" encoding="utf-8"?>
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:thermograph="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:background="@color/colorMainBackground"
     >

3.2 使用自定义的属性

 <?xml version="1.0" encoding="utf-8"?>
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:thermograph="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:background="@color/colorMainBackground"
     >

     <com.cnblogs.sjjg.tempview.Thermograph
         android:id="@+id/thermograph1"
         android:layout_width="10dp"
         android:layout_height="30dp"
         android:layout_marginStart="8dp"
         android:layout_marginLeft="8dp"
         android:layout_marginEnd="8dp"
         android:layout_marginRight="8dp"
         app:layout_constraintBottom_toBottomOf="@+id/thermograph2"
         app:layout_constraintEnd_toStartOf="@+id/thermograph2"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="@+id/thermograph2"
         thermograph:borderColor="@color/temp1_color"
         thermograph:coldValue="10"
         thermograph:hotValue="50"
         thermograph:maxValue="70"
         thermograph:minValue="-30" />

     <com.cnblogs.sjjg.tempview.Thermograph
         android:id="@+id/thermograph2"
         android:layout_width="100dp"
         android:layout_height="250dp"
         android:layout_marginStart="8dp"
         android:layout_marginLeft="8dp"
         android:layout_marginTop="32dp"
         android:layout_marginEnd="8dp"
         android:layout_marginRight="8dp"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintHorizontal_bias="0.5"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent"
         thermograph:coldValue="0"
         thermograph:hotValue="50"
         thermograph:maxValue="70"
         thermograph:minValue="-30" />

     <SeekBar
         android:id="@+id/seekBar"
         android:layout_width="0dp"
         android:layout_height="24dp"
         android:layout_marginStart="8dp"
         android:layout_marginLeft="8dp"
         android:layout_marginTop="32dp"
         android:layout_marginEnd="8dp"
         android:layout_marginRight="8dp"
         android:max="100"
         android:progress="50"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toBottomOf="@+id/thermograph2" />

 </androidx.constraintlayout.widget.ConstraintLayout>

4.在自定义的view中取属性值

     private void init(Context context,AttributeSet attrs){

         paint = new Paint(Paint.ANTI_ALIAS_FLAG);
         paint.setStyle(Paint.Style.FILL);

         setLayerType(View.LAYER_TYPE_SOFTWARE,paint);

         TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.thermograph);
         min = ta.getFloat(R.styleable.thermograph_minValue, -);
         max = ta.getFloat(R.styleable.thermograph_maxValue,);
         value = ta.getFloat(R.styleable.thermograph_thermoValue,);
         hot = ta.getFloat(R.styleable.thermograph_hotValue,);
         cold = ta.getFloat(R.styleable.thermograph_coldValue,);
         ratio = ta.getFloat(R.styleable.thermograph_ratio,0.25f);

         txtColor = ta.getColor(R.styleable.thermograph_textColor,Color.WHITE);

         int c = ContextCompat.getColor(context,R.color.temp_color);
         borderColor = ta.getColor(R.styleable.thermograph_borderColor,c);

         c = ContextCompat.getColor(context,R.color.temp_cold_color);
         contourColor = ta.getColor(R.styleable.thermograph_contourColor,c);

         c = ContextCompat.getColor(context,R.color.temp_hot_color);
         hotColor = ta.getColor(R.styleable.thermograph_hotColor,c);

         c = ContextCompat.getColor(context,R.color.temp_cold_color);
         coldColor = ta.getColor(R.styleable.thermograph_coldColor,c);

         showValue = ta.getBoolean(R.styleable.thermograph_showValue,true);

     }

     public Thermograph(Context context) {
         super(context);
         init(context,null);
     }

     public Thermograph(Context context, @Nullable AttributeSet attrs) {
         super(context, attrs);
         init(context,attrs);
     }

     public Thermograph(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
         init(context,attrs);
     }

     @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
     public Thermograph(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
         super(context, attrs, defStyleAttr, defStyleRes);
         init(context,attrs);
     }