[小tips] 各种编程小tips

许多这样的小tips, 记下来, 下次用到好找.

很简单

• Android 如何从底往上添加listview的items

android:stackFromBottom=”true”

• 打开一个页面时不自动弹出键盘

activity设置为

android:focusableInTouchMode=”true”

edittext去掉requestFocusable

• ListView，数据更新后自动scroll到底部

android:transcriptMode=”alwaysScroll”

• Action Bar 的item 显示为图标

android:showAsAction=”always”

• 由文件名生成Bitmap

File imgFile = new File(fileName);

Bitmap bitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());

• int与byte[]的互相转换

public static int bytesToInt(byte[] b) {
int value = 0;

for (int i = 0; i < 4; i++) {
int shift = i * 8;
value += (b[i] & 0x000000FF) << shift;
}

return value;
}

public static byte[] intToBytes(int a)
{
byte[] ret = new byte[4];

ret[0] = (byte) (a & 0xFF);
ret[1] = (byte) ((a >> 8) & 0xFF);
ret[2] = (byte) ((a >> 16) & 0xFF);
ret[3] = (byte) ((a >> 24) & 0xFF);

return ret;
}

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