前言
这里积累了一些不常见确又很实用的代码，每收集7条更新一次，希望能对大家有用。
声明
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正文
1、 精确获取屏幕尺寸（例如：3.5、4.0、5.0寸屏幕）
public static double getScreenPhysicalSize(Activity ctx) { DisplayMetrics dm = new DisplayMetrics(); ctx.getWindowManager().getDefaultDisplay().getMetrics(dm); double diagonalPixels = Math.sqrt(Math.pow(dm.widthPixels, 2) + Math.pow(dm.heightPixels, 2)); return diagonalPixels / (160 * dm.density); }
一般是7寸以上是平板
2、 判断是否是平板（官方用法）
public static boolean isTablet(Context context) { return (context.getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) >= Configuration.SCREENLAYOUT_SIZE_LARGE; }
3、 文字根据状态更改颜色 android:textColor
< selector xmlns:android ="http://schemas.android.com/apk/res/android" > < item android:color ="#53c1bd" android:state_selected ="true" /> < item android:color ="#53c1bd" android:state_focused ="true" /> < item android:color ="#53c1bd" android:state_pressed ="true" /> < item android:color ="#777777" /> </ selector >
放在res/color/目录下
4、背景色根据状态更改颜色 android:backgroup
< selector xmlns:android ="http://schemas.android.com/apk/res/android" > < item android:state_selected ="true" >< shape >
<gradient android:angle="0" android:centerColor="#00a59f" android:endColor="#00a59f" android:startColor="#00a59f" />
</shape></item> <item android:state_focused="true"><shape> <gradient android:angle="0" android:centerColor="#00a59f" android:endColor="#00a59f" android:startColor="#00a59f" /> </shape></item> <item android:state_pressed="true"><shape> <gradient android:angle="0" android:centerColor="#00a59f" android:endColor="#00a59f" android:startColor="#00a59f" /> </shape></item> <item><shape> <gradient android:angle="0" android:centerColor="#00ff00" android:endColor="00ff00" android:startColor="00ff00" /> </shape></item></selector>如果直接给背景色color会报错。
5、 启动APK的默认Activity
public static void startApkActivity( final Context ctx, String packageName) { PackageManager pm = ctx.getPackageManager(); PackageInfo pi; try { pi = pm.getPackageInfo(packageName, 0); Intent intent = new Intent(Intent.ACTION_MAIN, null); intent.addCategory(Intent.CATEGORY_LAUNCHER); intent.setPackage(pi.packageName); List<ResolveInfo> apps = pm.queryIntentActivities(intent, 0); ResolveInfo ri = apps.iterator().next(); if (ri != null) { String className = ri.activityInfo.name; intent.setComponent( new ComponentName(packageName, className)); ctx.startActivity(intent); } } catch (NameNotFoundException e) { Log.e("startActivity", e); } }
7、计算字宽
public static float GetTextWidth(String text, float Size) { TextPaint FontPaint = new TextPaint(); FontPaint.setTextSize(Size); return FontPaint.measureText(text); }
注意如果设置了textStyle，还需要进一步设置TextPaint。