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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>