Skip to content

Latest commit

 

History

History
113 lines (98 loc) · 3.2 KB

AndroidDevCodeBlock.md

File metadata and controls

113 lines (98 loc) · 3.2 KB

Android 开发常用代码块

  1. 防止Handler造成内存泄漏，避免使用非静态内部类，继承Handler时，要么是放在单独的类文件中，要么就是使用静态内部类

    private static class MyHandler extends Handler {
        private WeakReference<MainActivity> activityWeakReference;

        public MyHandler(MainActivity activity) {
            activityWeakReference = new WeakReference<>(activity);
        }

        @Override
        public void handleMessage(Message msg) {
            MainActivity activity = activityWeakReference.get();
            if (activity != null) {
                out.println(".");
            }
        }
    }

2.swiperefreshlayout,第一次进入页面的时候显示加载进度条

   mSwipeRefreshLayout.post(new Runnable() {
    @Override    
   public void run() {
       mSwipeRefreshLayout.setRefreshing(true);
    }
});

3.消除A页面到A页面之间的页面，例如A->B->C->A，

   Intent intent = new Intent(C.this, A.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(intent);

或在AndroidManifest.xml中设置Activity的启动模式为singleTask

4.替换AndroidManifest中的占位符 build文件

   buildTypes {
        dev {
            debuggable true
            //替换AndroidManifest中的占位符
            manifestPlaceholders = [
                    //环信应用的appkey
                    "emAppKey": "11721dev",
            ]
           }
            
            test {
            debuggable true
            //替换AndroidManifest中的占位符
            manifestPlaceholders = [
                    //环信应用的appkey
                    "emAppKey": "11721test",
            ]
           }
        }

AndroidManifest.xml

   <!-- 设置环信应用的appkey -->
        <meta-data
            android:name="EASEMOB_APPKEY"
            android:value="${emAppKey}" />

5.拨打电话 Intent.ACTION_DIAL直接拨打 需要权限 Intent.FLAG_ACTIVITY_NEW_TASK 跳转到拨号界面，不需要权限

         //原来用Intent.ACTION_DIAL，会跳到拨号界面
        Intent intent = new Intent(Intent.ACTION_DIAL, Uri.parse("tel:" + "10086"));
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(intent);

6.webview全屏显示image

   String imgSrcHtml = "<html><img src='" + url + "' style='width:100%;height:auto'/></html>";
   mWebView.loadData(imgSrcHtml, "text/html", "UTF-8");

7.Dp,Px之间的转换

public class DensityUtils {

    public static int dpToPx(int dp) {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, Resources.getSystem().getDisplayMetrics());
    }

    public static int pxToDp(float px) {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, px, Resources.getSystem().getDisplayMetrics());
    }
}

8.虚线

<shape xmlns:android="http://schemas.android.com/apk/res/android"
       android:shape="line">

    <stroke
        android:width="1dp"
        android:dashWidth="5dp"
        android:dashGap="5dp"
        android:color="#33000000"/>

</shape>