SetWidth (int 像素)使用的是 dip 还是 px？

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Pixels of course, the method is asking for pixels as parameter.

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最佳答案

It uses pixels, but I'm sure you're wondering how to use dips instead. The answer is in TypedValue.applyDimension(). Here's an example of how to convert dips to px in code:

// Converts 14 dip into its equivalent px
Resources r = getResources();
int px = Math.round(TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, 14,r.getDisplayMetrics()));

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The correct way to obtain a constant number of DIPs in code is to create a resources XML file containing dp values a bit like:

<?xml version="1.0" encoding="utf-8"?>
<resources>
<dimen name="image_width">100dp</dimen>
<dimen name="image_height">75dp</dimen>
</resources>

Then refer to the resource in your code like so:

float width = getResources().getDimension(R.dimen.image_width));
float height = getResources().getDimension(R.dimen.image_height));

The float you have returned will be scaled accordingly for the pixel density of the device and so you don't need to keep replicating a conversion method throughout your application.

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Method setWidth(100), set 100 px as width(not in dp).So you may face width varying problems on different android phones.So use measurement in dp instead of pixels.Use the below code to get measurement in dp of sample width=300px and height=400px.

int width = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 300, getResources().getDisplayMetrics());


int Height = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 400, getResources().getDisplayMetrics());

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float dps = 100;
float pxs = dps * getResources().getDisplayMetrics().density;

Source (@Romain Guy)

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Based on above answers which works fine to me, i generate some helper methods, just add them in your utils to use them in whole project.

   // value in DP
public static int getValueInDP(Context context, int value){
return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, value, context.getResources().getDisplayMetrics());
}


public static float getValueInDP(Context context, float value){
return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, value, context.getResources().getDisplayMetrics());
}


// value in PX
public static int getValueInPixel(Context context, int value){
return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, value, context.getResources().getDisplayMetrics());
}


public static float getValueInPixel(Context context, float value){
return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, value, context.getResources().getDisplayMetrics());
}

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It uses pixels. here's a Kotlin extension function to convert pixels to dp

fun Context.pxToDp(value: Float):Int{
val r: Resources = resources
return TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, value, r.displayMetrics
).roundToInt()
}