Android studio list of useful shortcuts or like Eclipse
File -> Settings -> Keymap you can do select Eclipse keymap from drop down menu
Ctrl+Shift+A (Help | Find Action on the main menu) and start typing the name of the action. Choose the desired action from the suggestion list.
Ctrl+Click (on Windows) or Cmd+Click (on MacOS) a tab in the editor to navigate to any part of the file path. Select the necessary element in the drop-down, and the corresponding file path opens in an external browser (e.g., in the Explorer, if your OS is Windows).
Ctrl+F find
Refactor | Rename: Shift+F6 ( +F6)
Find and replace: CTRL + R
Go to variable declaration: CTRL + B
Ctrl+Shift+I (View | Quick Definition)
Ctrl+Alt+F7 (Edit | Find | Show Usages in the main menu)
Ctrl+Shift+F find in project
Ctrl+Shift+F7 (Edit | Find | Highlight Usages in File) to quickly highlight usages of some variable in the current file.
Use F3 and Shift+F3 keys to navigate through highlighted usages.
Press Escape to remove highlighting.
Ctrl+W (extend selection) in the editor selects the word at the caret and then selects expanding areas of the source code. For example, it may select a method name, then the expression that calls this method, then the whole statement, then the containing block, etc. You can also select the word at the caret and the expanding areas of the source code by double-clicking the target areas in the editor.
To search through the classes, files, tool windows, actions, settings, and symbols of your project by double pressing the Shift key
Ctrl+P (View | Parameter Info) e.g. localURL = new URL(localUrlString); select localUrlString and press Ctrl + P
Show html documentation tooltips: CTRL + Q
Comment uncomment single line: CTRL + /
Comment uncomment selected text: CTRL + SHIFT + /
Code completion (Ctrl+Space)
Alt key and mouse pointer dragging for column selection
If nothing is selected in the editor, and you press Ctrl+C, then the whole line at caret is copied to the clipboard.
Ctrl + Delete delete word from caret to end.
Ctrl + Backspace delete word from caret to start.
Duplicate line: CTRL + D
To compare two directories,or jar files, select one or both of them in the Project view and press Ctrl+D.
Editor Delete Line: CTRL + Y
Move line UP, DOWN. Select a code fragment and press Ctrl+Shift+Up or Ctrl+Shift+Down.
To open any class or file in the editor at the desired line, press Ctrl+Shift+N (Navigate | File), start typing the name, and choose the one from the suggestion list. Then type the colon (:) and a line number
Ctrl+Shift+Enter to complete a current statement such as if, do-while, try-catch, return (or a method call)
Alt+Enter to invoke a quick fix or intention action, press the right arrow key to reveal the list of additional options.
To quickly review your recent changes to the project: Alt+Shift+C
Code Completion, you can accept the currently highlighted selection in the popup list with the period character (.), comma (,), semicolon (;), space and other characters.
Quickly move between methods in the editor: Alt+Up and Alt+Down
Ctrl+Shift+J shortcut joins two lines into one and removes unnecessary space to match your code style
Ctrl+Shift+V to choose and insert recent clipboard contents into the text
Inheritance hierarchy for a selected class: Ctrl+H
Right-clicking on a breakpoint marker you can quickly enable/disable the breakpoint or adjust its properties.
Evaluate the value of any expression while debugging the program, select its text in the editor (you may press a Ctrl+W a few times to efficiently perform this operation) and press Alt+F8.
Quickly evaluate the value of any expression while debugging the program, hold Alt and click this expression to see its value and calculate it, call a method, etc.
You can use the Extract Variable refactoring even on incomplete statements. Just select the necessary block in the editor and press Ctrl+Alt+V.
To open any particular method or field in editor: Ctrl+Alt+Shift+N
Add unimplemented methods: CTRL + I
Override methods: CTRL + O
Format code: CTRL + ALT + L
Show project: ALT + 1
Show logcat: ALT + 6
Hide project - logcat: SHIFT + ESC
Build: CTRL + F9
Build and Run: CTRL + F10
Alt+Shift+F10 access the Run/Debug dropdown on the main toolbar
Collapse all: CTRL + SHIFT + NumPad +
Expand all: CTRL + SHIFT + NumPad -
Ctrl+Shift+A (Help | Find Action on the main menu) and start typing the name of the action. Choose the desired action from the suggestion list.
Ctrl+Click (on Windows) or Cmd+Click (on MacOS) a tab in the editor to navigate to any part of the file path. Select the necessary element in the drop-down, and the corresponding file path opens in an external browser (e.g., in the Explorer, if your OS is Windows).
Find - Rename
Ctrl+F find
Refactor | Rename: Shift+F6 ( +F6)
Find and replace: CTRL + R
Go to variable declaration: CTRL + B
Ctrl+Shift+I (View | Quick Definition)
Ctrl+Alt+F7 (Edit | Find | Show Usages in the main menu)
Ctrl+Shift+F find in project
Ctrl+Shift+F7 (Edit | Find | Highlight Usages in File) to quickly highlight usages of some variable in the current file.
Use F3 and Shift+F3 keys to navigate through highlighted usages.
Press Escape to remove highlighting.
Ctrl+W (extend selection) in the editor selects the word at the caret and then selects expanding areas of the source code. For example, it may select a method name, then the expression that calls this method, then the whole statement, then the containing block, etc. You can also select the word at the caret and the expanding areas of the source code by double-clicking the target areas in the editor.
To search through the classes, files, tool windows, actions, settings, and symbols of your project by double pressing the Shift key
Ctrl+P (View | Parameter Info) e.g. localURL = new URL(localUrlString); select localUrlString and press Ctrl + P
Show html documentation tooltips: CTRL + Q
Edit
Comment uncomment single line: CTRL + /
Comment uncomment selected text: CTRL + SHIFT + /
Code completion (Ctrl+Space)
Alt key and mouse pointer dragging for column selection
If nothing is selected in the editor, and you press Ctrl+C, then the whole line at caret is copied to the clipboard.
Ctrl + Delete delete word from caret to end.
Ctrl + Backspace delete word from caret to start.
Duplicate line: CTRL + D
To compare two directories,or jar files, select one or both of them in the Project view and press Ctrl+D.
Editor Delete Line: CTRL + Y
Move line UP, DOWN. Select a code fragment and press Ctrl+Shift+Up or Ctrl+Shift+Down.
To open any class or file in the editor at the desired line, press Ctrl+Shift+N (Navigate | File), start typing the name, and choose the one from the suggestion list. Then type the colon (:) and a line number
Ctrl+Shift+Enter to complete a current statement such as if, do-while, try-catch, return (or a method call)
Alt+Enter to invoke a quick fix or intention action, press the right arrow key to reveal the list of additional options.
To quickly review your recent changes to the project: Alt+Shift+C
Code Completion, you can accept the currently highlighted selection in the popup list with the period character (.), comma (,), semicolon (;), space and other characters.
Quickly move between methods in the editor: Alt+Up and Alt+Down
Ctrl+Shift+J shortcut joins two lines into one and removes unnecessary space to match your code style
Ctrl+Shift+V to choose and insert recent clipboard contents into the text
Inheritance hierarchy for a selected class: Ctrl+H
Right-clicking on a breakpoint marker you can quickly enable/disable the breakpoint or adjust its properties.
Evaluate the value of any expression while debugging the program, select its text in the editor (you may press a Ctrl+W a few times to efficiently perform this operation) and press Alt+F8.
Quickly evaluate the value of any expression while debugging the program, hold Alt and click this expression to see its value and calculate it, call a method, etc.
You can use the Extract Variable refactoring even on incomplete statements. Just select the necessary block in the editor and press Ctrl+Alt+V.
To open any particular method or field in editor: Ctrl+Alt+Shift+N
Add unimplemented methods: CTRL + I
Override methods: CTRL + O
Format code: CTRL + ALT + L
Show project: ALT + 1
Show logcat: ALT + 6
Hide project - logcat: SHIFT + ESC
Build: CTRL + F9
Build and Run: CTRL + F10
Alt+Shift+F10 access the Run/Debug dropdown on the main toolbar
Collapse all: CTRL + SHIFT + NumPad +
Expand all: CTRL + SHIFT + NumPad -
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Constructor SimpleCursorAdapter is deprecated.
If using api 11 and above, you can try add last parameter 0.
If using api 11 and above, you can try add last parameter 0.
Cursor cursor = managedQuery(...........,,,,);
// Specify the columns we want to display in the result
String[] from = new String[] { KEY_WORD,
KEY_DEFINITION };
// Specify the corresponding layout elements where we want the columns to go
int[] to = new int[] { R.id.word,
R.id.definition };
// deprecated
SimpleCursorAdapter words =
new SimpleCursorAdapter(this,
R.layout.result, cursor, from, to);
// working
SimpleCursorAdapter words =
new SimpleCursorAdapter(this,
R.layout.result, cursor, from, to, 0); // to, 0!!!!
//working in Fragment
SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(getActivity(),
android.R.layout.simple_list_item_2, null,
new String[] { "name", "age" }, // cursor parameters
new int[] { android.R.id.text1, android.R.id.text2 }, 0);
Map TreeMap key value pair, Map sort by key, Iterator for Map Java Android example.
MainClass.java
MainClass.java
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
public class MainClass {
public static void main(String[] arg) {
// english;germany dictionary
String[] arrayOfString = { "one;eine", "two;zwei", "three;drei", "four;vier" };
Map<String, String> map = new TreeMap<String, String>();
for(String s: arrayOfString){
String[] array = s.split(";");
String sKey ="", sValue="";
if(array.length > 1){
sKey = array[0]; sValue = array[1];
map.put(sKey, sValue);
}
}
List sortedByKeys=new ArrayList(map.keySet());
Collections.sort(sortedByKeys);
// iterate map
Set references = map.keySet();
Iterator it = references.iterator();
while (it.hasNext()) {
String key = (String) it.next();
String value = map.get(key);
System.out.println(key + " = " + value);
}
// or other example how iterate map
TreeSet<String> keys = new TreeSet<String>(map.keySet());
for (String key : keys) {
String value = map.get(key);
System.out.println(key + " = " + value);
}
// check if key exists
// if( map.containsKey("two")){
// System.out.print("two = " + map.get("two"));
// }
}
}
/*
four = vier
one = eine
three = drei
two = zwei
*/
Throws multiple exceptions Java example source code
public void callFc()
throws IndexOutOfBoundsException, ArithmeticException
{
// my code for example:
String[] sArray = {"aa","bb"};
String str = sArray[5]; // IndexOutOfBoundsException
int n = 5 / 0; // ArithmeticException
}
public void someFC (){
try{
callFc();
}
catch(IndexOutOfBoundsException e){
Log.e("TAG", e.toString());
}
catch(ArithmeticException e2){
Log.e2("TAG",e2.toString());
}
}
How to change the image dynamically in ImageView and button setOnClickListener Android sample.
Main.java
main.xml
Put into res/drawable this pictures:
Main.java
ipackage cz.okhelp.my_game;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
public class Main extends Activity {
private ImageView hImageViewSemafor;
private Button hButton;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
hImageViewSemafor = (ImageView)findViewById(R.id.idImageViewSemafor);
hButton = (Button) findViewById(R.id.idBtnChangeImage);
hButton.setOnClickListener(mButtonChangeImageListener);
}
View.OnClickListener mButtonChangeImageListener = new OnClickListener() {
public void onClick(View v) {
// setImageResource will change image in ImageView
hImageViewSemafor.setImageResource(R.drawable.semafor_green);
}
};
}
main.xml
Put into res/drawable this pictures:


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="//schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<ImageView
android:src="@drawable/semafor_red"
android:id="@+id/idImageViewSemafor"
android:background="#66FFFFFF"
android:adjustViewBounds="true"
android:maxWidth="47dip"
android:maxHeight="91dip"
android:padding="10dip"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
Warning: The application may be doing too much work on its main thread
Try this sorce code:
Try this sorce code:
import android.os.StrictMode;
public class MyActivity extends Activity {
static{
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}
@Override
public void onCreate(Bundle savedInstanceState) {
//.................. etc.
Editace: 2015-11-09 15:04:31
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Url:android-studio-list-of-useful-shortcuts