Round number float - double to int - long Java example
int nf = Math.round(5.789f);
System.out.print(nf); // 6
float f = 28.611f;
int n3 = Math.round(f);
System.out.println(n3); // 29
double d = 1234.56;
long lon = Math.round(d);
System.out.println(lon); // 1235
int diff = 90 - 40;
// float fDeleni = diff / 10; // error code
float fDeleni = (float)diff / 10.f; // ok
int nRound = Math.round(fDeleni);
// Caution:
int n2 = (int) 8.999f;
System.out.println(n2); // 8
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String [] arOfStrings = {"one", "two", "three"};
List<String> mListOfStrings = new ArrayList<String>(Arrays.asList(arOfStrings));
Collections.shuffle(mListOfstrings);
String str = mListOfStrings.get(2);// 2 is index of pozition an element
int [] arOfInt = {1, 2, 3};
List<Integer> mListOfInt = new ArrayList<Integer>(Arrays.asList(arOfInt));
Collections.shuffle(mListOfInt);
Problem: erroneous entry of id
Solution: @+id/
<RadioButton android:id="idRadio"
android:text="My radio button"/>
Solution: @+id/
<RadioButton android:id="@+id/idRadio"
android:text="My radio button"/>
Try some solution - each individually or all
- Check AndroidManifest.xml activity declaration
<activity android:name=".EnableProfileActivity" android:label="@string/app_name" /> - Delete BUILD folder in module tree and Clean / Rebuild project
- Restart Android Studio
// image from res/drawable
int resID = getResources().getIdentifier("my_image",
"drawable", getPackageName());
// view
int resID = getResources().getIdentifier("my_resource",
"id", getPackageName());
// string
int resID = getResources().getIdentifier("my_string",
"string", getPackageName());
Why the app selects data from basic layout folder if smallest width is higher then the number in folder name?
Example 1
layout-sw600dp values-sw600dp (smallest width sw for data usage from this folder is 600dp density independent pixel!!!!!)
Device screen resolution is 1200 x 900 px (pixel) Wow, app to be select data from sw600dp folder! Realy?
DPI of device screen - dot per inch (pixel per inch) is 480 pixel it is wery important number!
In our case smallest dimension of screen must be at least 1800 real - physical pixels (1800 px / 3 ratio(dpi/160) = 600 dp (dip density independend pixels) to be used data from folders values-sw600dp and layout-sw600dp.
Example 2 see Example 1 abouve
Device: Nexus 7 (2012) selected from Android Studio tool layout editor
Resolution: 800x1280 px
DPI: tvdpi (approximately 213dpi)
Ratio: 1.33 (213 / 160)
Smallest width in px: 800
Convert px to dp: 601.5 (800 / 1.33)
Result:Smallest width is 601.5dp The App to be used data from folders values-sw600dp and layout-sw600dp.
Example 1
layout-sw600dp values-sw600dp (smallest width sw for data usage from this folder is 600dp density independent pixel!!!!!)
Device screen resolution is 1200 x 900 px (pixel) Wow, app to be select data from sw600dp folder! Realy?
DPI of device screen - dot per inch (pixel per inch) is 480 pixel it is wery important number!
- App selects smallest dimension of screen. In our case 900 px
Medium screen have 160 dpi (The density-independent pixel is equivalent to one physical pixel on a 160 dpi screen, which is the baseline density assumed by the system for a "medium" density screen.). - App calculate ratio 480 / 160 = 3 (The conversion of dp units to screen pixels: px = dp * (dpi / 160))
- App calculate smallest dimesnion of screen in dp 900 / 3 = 300 dip or dp (density independed pixel).
- App selects data from basic values and layout folder because sw600dp is greater than 300dp.
In our case smallest dimension of screen must be at least 1800 real - physical pixels (1800 px / 3 ratio(dpi/160) = 600 dp (dip density independend pixels) to be used data from folders values-sw600dp and layout-sw600dp.
Example 2 see Example 1 abouve
Device: Nexus 7 (2012) selected from Android Studio tool layout editor
Resolution: 800x1280 px
DPI: tvdpi (approximately 213dpi)
Ratio: 1.33 (213 / 160)
Smallest width in px: 800
Convert px to dp: 601.5 (800 / 1.33)
Result:Smallest width is 601.5dp The App to be used data from folders values-sw600dp and layout-sw600dp.
Editace: 2012-07-15 14:42:42
Počet článků v kategorii: 396
Url:round-number-float-to-int-java-example
