Android 常用API

1、onItemClick

public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3)
各项的意义：arg1是当前item的view，通过它可以获得该项中的各个组件。
例如arg1.textview.settext("asd");

arg2是当前item的ID。这个id根据你在适配器中的写法可以自己定义。

arg3是当前的item在listView中的相对位置！

2、shader

/** Create a shader that draws a radial gradient given the center and radius.
@param centerX The x-coordinate of the center of the radius
@param centerY The y-coordinate of the center of the radius
@param radius Must be positive. The radius of the circle for this gradient
@param centerColor The color at the center of the circle.
@param edgeColor The color at the edge of the circle.
@param tileMode The Shader tiling mode
*/
public RadialGradient(float centerX, float centerY, float radius,
int centerColor, int edgeColor, @NonNull TileMode tileMode) {
if (radius <= 0) {
throw new IllegalArgumentException("radius must be > 0");
}
mType = TYPE_COLOR_CENTER_AND_COLOR_EDGE;
mX = centerX;
mY = centerY;
mRadius = radius;
mCenterColor = centerColor;
mEdgeColor = edgeColor;
mTileMode = tileMode;
init(nativeCreate2(centerX, centerY, radius, centerColor, edgeColor, tileMode.nativeInt));
}