判断资源存在与否如判断一个drawable的图片存在及通过id加载图片

判断资源存在与否如判断一个drawable的图片存在及通过id加载图片

int i= getResources().getIdentifier("icon", "drawable", getPackageName()) ;
if(i>0)
{Log.i("aa","aa");}
else
{Log.i("vbv","aa");}

或者

int resID = getResources().getIdentifier("org.loveandroid.androidtest:drawable/gallery_photo_1",null,null);

int resID = getResources
(
).
getIdentifier
(
"org.anddev.android.testproject:drawable/bug",
null,
null
);

// or

int resID = getResources
(
).
getIdentifier
(
"bug",
"drawable",
"org.anddev.android.testproject"
);

第一个参数其实

full_package:type/filename_without_ending是这种格式 然后其他的可以为null

int idFlag = getResources().getIdentifier(

getPackageName() + ":drawable/flag",

null, null);

// 或是

int idFlag = getResources().getIdentifier(

"flag", "drawable", getPackageName());

int idFlag = getResources().getIdentifier(
getPackageName() + ":drawable/flag",
null, null);
// 或是
int idFlag = getResources().getIdentifier(
"flag", "drawable", getPackageName());

var Drawable[] dw = new Drawable[10];

for (int i = 1; i <= 10; i++) {

int id = getResources().getIdentifier(

"flag" + i,

"drawable", getPackageName());
3ff0

dw[i-1] = getResources().getDrawable(id);

}

var Drawable[] dw = new Drawable[10];

for (int i = 1; i <= 10; i++) {
int id = getResources().getIdentifier(
"flag" + i,
"drawable", getPackageName());
dw[i-1] = getResources().getDrawable(id);
}

用反射发 可以得到 所有的资源
private void

_DumpAllResourceIDs(Class<?> classType)

throws IllegalArgumentException {

Field[] fIDs = classType.getFields();

try {

for (int i = 0; i < fIDs.length; i++) {

Field fld = fIDs[i];

int nID = fld.getInt(null);

Log.d("dbg",

classType.getSimpleName() + " " +

i + ": " +

fld.getName() + "=" +

nID);

}

} catch (Exception e) {

throw new IllegalArgumentException();

}

}

private void
_DumpAllResourceIDs(Class<?> classType)
throws IllegalArgumentException {
Field[] fIDs = classType.getFields();

try {
for (int i = 0; i < fIDs.length; i++) {
Field fld = fIDs[i];
int nID = fld.getInt(null);
Log.d("dbg",
classType.getSimpleName() + " " +
i + ": " +
fld.getName() + "=" +
nID);
}
} catch (Exception e) {
throw new IllegalArgumentException();
}
}

import java.lang.reflect.Field;

...

_DumpAllResourceIDs(R.layout.class);

_DumpAllResourceIDs(R.drawable.class);

import java.lang.reflect.Field;
...
_DumpAllResourceIDs(R.layout.class);
_DumpAllResourceIDs(R.drawable.class);

结果

R$layout 0: main=2130903040

R$layout 1: small_spinner_dropdown_item=2130903041

R$drawable 0: icon=2130837504