Android 自定义View时使用TypedArray配置样式属性详细介绍

/** 
 * @title ExpandTextView 
 * @description 可扩展TextView，可以通过设置ExpandTextViewStyle来自定义展开图片、收起图片和最小展示的行数 
 */ 
public class ExpandTextView extends LinearLayout implements OnClickListener { 
  /** 
   * 默认最少展示的行数 
   */ 
  private int defaultMinLines; 
  /** 
   * 是否展开 
   */ 
  private boolean mCollapsed = true; 
  /** 
   * 是否重新布局 
   */ 
  private boolean mRelayout = false; 
 
  private View expandView; 
  private TextView expandText; 
  private ImageView expandImg; 
  private Drawable mExpandDrawable; 
  private Drawable mCollapseDrawable; 
 
  public ExpandTextView(Context context) { 
    this(context, null); 
  } 
 
  public ExpandTextView(Context context, AttributeSet attrs) { 
    super(context, attrs); 
    init(attrs); 
  } 
 
  private void init(AttributeSet attrs) { 
    expandView = LayoutInflater.from(getContext()).inflate( 
        R.layout.pt__expand_textview, null); 
    expandText = (TextView) expandView.findViewById(R.id.expand_text); 
    expandText.setOnClickListener(this); 
    expandImg = (ImageView) expandView.findViewById(R.id.expand_img); 
    expandImg.setOnClickListener(this); 
 
    TypedArray a = getContext().obtainStyledAttributes(attrs, 
        R.styleable.ExpandTextViewStyle); 
    // 自定义图片资源 
    mExpandDrawable = getResources().getDrawable( 
        a.getResourceId(R.styleable.ExpandTextViewStyle_expand, 
            R.drawable.pt__ic_expand)); 
    expandImg.setBackgroundDrawable(mExpandDrawable); 
    mCollapseDrawable = getResources().getDrawable( 
        a.getResourceId(R.styleable.ExpandTextViewStyle_collapse, 
            R.drawable.pt__ic_collapse)); 
    // 自定义最小行数 
    defaultMinLines = a.getInt( 
        R.styleable.ExpandTextViewStyle_default_min_lines, 2); 
    a.recycle(); 
 
    LinearLayout.LayoutParams params = new LayoutParams( 
        LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT); 
    params.gravity = Gravity.CENTER; 
    addView(expandView, params); 
  } 
 
  @Override 
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 
    if (!mRelayout) { 
      super.onMeasure(widthMeasureSpec, heightMeasureSpec); 
      return; 
    } 
    mRelayout = false; 
    expandText.setMaxLines(Integer.MAX_VALUE); 
    expandImg.setVisibility(View.GONE); 
    super.onMeasure(widthMeasureSpec, heightMeasureSpec); 
    if (expandText.getLineCount() <= defaultMinLines) { 
      return; 
    } 
    if (mCollapsed) { 
      expandText.setMaxLines(defaultMinLines); 
    } 
    expandImg.setVisibility(View.VISIBLE); 
    super.onMeasure(widthMeasureSpec, heightMeasureSpec); 
  } 
 
  public void setText(CharSequence text) { 
    mRelayout = true; 
    expandText.setText(text); 
  } 
 
  public void setText(int resId) { 
    this.setText(getContext().getString(resId)); 
  } 
 
  @Override 
  public void onClick(View view) { 
    if (expandImg.getVisibility() != View.VISIBLE) { 
      return; 
    } 
    mCollapsed = !mCollapsed; 
    expandImg.setBackgroundDrawable(mCollapsed ? mExpandDrawable 
        : mCollapseDrawable); 
    expandText 
        .setMaxLines(mCollapsed ? defaultMinLines : Integer.MAX_VALUE); 
  } 
} 

<resources> 
 
  <!-- ******************************可扩展ExpandTextView样式******************************* --> 
  <declare-styleable name="ExpandTextViewStyle"> 
 
    <!-- 展开图片 --> 
    <attr name="expand" format="reference" /> 
    <!-- 关闭图片 --> 
    <attr name="collapse" format="reference" /> 
    <!-- 最小行数 --> 
    <attr name="default_min_lines" format="integer" /> 
  </declare-styleable> 
 
</resources> 

<!-- 可扩展ExpandTextView样式 --> 
  <style name="ExpandTextViewStyle"> 
    <item name="expand">@drawable/pt__ic_expand</item> 
    <item name="collapse">@drawable/pt__ic_collapse</item> 
    <item name="default_min_lines">3</item> 
  </style> 

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
  xmlns:custom="http://schemas.android.com/apk/res/com.example.typedarraytest" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  android:paddingBottom="@dimen/activity_vertical_margin" 
  android:paddingLeft="@dimen/activity_horizontal_margin" 
  android:paddingRight="@dimen/activity_horizontal_margin" 
  android:paddingTop="@dimen/activity_vertical_margin" > 
 
  <com.example.typedarraytest.ExpandTextView 
    android:id="@+id/expand_text_view" 
    style="@style/ExpandTextViewStyle" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:layout_margin="8dp" 
    custom:default_min_lines="2" /> 
 
</RelativeLayout> 

TypedArray a = getContext().obtainStyledAttributes(attrs, 
    R.styleable.ExpandTextViewStyle); 
// 自定义图片资源 
mExpandDrawable = getResources().getDrawable( 
    a.getResourceId(R.styleable.ExpandTextViewStyle_expand, 
        R.drawable.pt__ic_expand)); 
expandImg.setBackgroundDrawable(mExpandDrawable); 
mCollapseDrawable = getResources().getDrawable( 
    a.getResourceId(R.styleable.ExpandTextViewStyle_collapse, 
        R.drawable.pt__ic_collapse)); 
// 自定义最小行数 
defaultMinLines = a.getInt( 
    R.styleable.ExpandTextViewStyle_default_min_lines, 2); 
a.recycle();