Android Interface/Native Android GUI
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Android API Hello World in Pascal
Here is an example Pascal application written for Android. It shows how to create controls, receive callback events and how to use the timer.
The full directory structure can be download with this svn command:
svn co https://p-tools.svn.sourceforge.net/svnroot/p-tools/turbochessclock4android turbochessclock4android
Here is the Pascal code from this example:
<delphi> {
A simple Chess Clock application
Author: Felipe Monteiro de Carvalho - 2011 License: Public Domain
} program turbochessclock4android;
{$mode objfpc}{$H+}
uses
Classes, SysUtils, androidpipescomm, androidview, javalang, androidapp, androidtimer, androidutil;
type
TEventHandler = class public procedure HandleOnTimer(ASender: TObject); procedure buttonStartClickCallback(v: TView); procedure buttonMoveClickCallback(v: TView); end;
var
layout: TLinearLayout; params: TLayoutParams; tv, black_label, white_label: TTextView; scroller: TScrollView; btn_move, btn_start: TButton; tp: TTimePicker; WhiteTimeCount: Integer = 0; BlackTimeCount: Integer = 0; MyTimer: TAndroidTimer; MyEventHandler: TEventHandler; IsWhitePlayerMove: Boolean = True;
procedure TEventHandler.buttonStartClickCallback(v: TView); begin
black_label.setVisibility(VISIBLE); white_label.setVisibility(VISIBLE); btn_move.setVisibility(VISIBLE); // WhiteTimeCount := tp.getCurrentHour() * 60 * 60 + tp.getCurrentMinute() * 60; BlackTimeCount := WhiteTimeCount; // MyTimer.removeCallbacks(); MyTimer.postDelayed(100);
end;
procedure TEventHandler.buttonMoveClickCallback(v: TView); begin
IsWhitePlayerMove := not IsWhitePlayerMove;
end;
procedure TEventHandler.HandleOnTimer(ASender: TObject); var
lSeconds, lMinutes, lHours: Integer;
begin
if IsWhitePlayerMove then begin lSeconds := WhiteTimeCount mod 60; lMinutes := (WhiteTimeCount mod (60 * 60)) div 60; lHours := WhiteTimeCount div (60 * 60); white_label.setText(Format('White %d:%d:%d', [lHours, lMinutes, lSeconds])); // if WhiteTimeCount = 0 then Exit; Dec(WhiteTimeCount); end else begin lSeconds := BlackTimeCount mod 60; lMinutes := (BlackTimeCount mod (60 * 60)) div 60; lHours := BlackTimeCount div (60 * 60); black_label.setText(Format('Black %d:%d:%d', [lHours, lMinutes, lSeconds])); // if BlackTimeCount = 0 then Exit; Dec(BlackTimeCount); end; // MyTimer.removeCallbacks(); // Note that this has a low precision, but it enough for this simple app // A more precise app would keep another time count instead of just using Dec // at each timer call MyTimer.postDelayed(1000);
end;
begin
// Here add any initialization. // Any initialization code will be run inside Activity.onCreate, // so keep it as short as possible! // It should mostly contain GUI initialization // User interface MyEventHandler := TEventHandler.Create;
// Prepares the UI of the program layout := TLinearLayout.Create; params := TLayoutParams.Create(androidview.FILL_PARENT, androidview.FILL_PARENT); layout.setLayoutParams(params); params.Free; layout.setOrientation(androidview.VERTICAL);
// Game UI
black_label := TTextView.Create; black_label.setText('Black time:'); black_label.setVisibility(GONE); black_label.setTextSize(COMPLEX_UNIT_PX, 40); layout.addView(black_label);
white_label := TTextView.Create; white_label.setText('White time:'); white_label.setVisibility(GONE); white_label.setTextSize(COMPLEX_UNIT_PX, 40); layout.addView(white_label);
btn_move := TButton.Create; btn_move.setText('Move finished!'); btn_move.setOnClickListener(@MyEventHandler.buttonMoveClickCallback); btn_move.setVisibility(GONE); layout.addView(btn_move);
// Config UI
tv := TTextView.Create; tv.setText('Please select how much to give to the players and press "Start Game":'); layout.addView(tv);
tp := TTimePicker.Create; tp.setIs24HourView(True); tp.setCurrentHour(0); tp.setCurrentMinute(30); layout.addView(tp);
btn_start := TButton.Create; btn_start.setText('Start game!'); btn_start.setOnClickListener(@MyEventHandler.buttonStartClickCallback); layout.addView(btn_start);
// And also allow the user to scroll the UI if it is larger then the screen width // Scrolling takes place only horizontally
scroller := TScrollView.Create; scroller.addView(layout);
Activity.setContentView(scroller);
MyTimer := TAndroidTimer.Create; MyTimer.OnTimer := @MyEventHandler.HandleOnTimer;
// Now tell Java that the initialization has finished vAndroidPipesComm.onCreateFinished(); // Here you can add any other initialization, // specially non-GUI code
// Now we block our execution waiting for callbacks from Java vAndroidPipesComm.MessageLoop();
end. </delphi>
Compiling the example project in Linux
1> Get a working arm-linux cross-compiler which generates ARMv5 eabi with softfloat (as many phones like HTC Wildfire have no FPU)
To do this one can download an unofficial build from here:
http://members.yline.com/~tom_at_work/fpc-2.4.2.UNOFFICIAL.arm-linux.tar . Compiled for ARMv5 eabi with softfloat.
Or build your own. There are instructions here: Setup_Cross_Compile_For_ARM
2> Install the Android SDK. Instructions here: Android_Interface/Using_the_Android_SDK,_Emulator_and_Phones#Using_the_Android_SDK
3> Install ant, for example in Mandriva Linux:
urpmi ant
4> Open the project turbochessclock/turbochessclock4android.lpi in Lazarus and build it
5> Build the APK file in debug mode
ant debug
6> Connect your phone and make sure you can connect to it via ADB. More info here: Android_Interface/Using_the_Android_SDK,_Emulator_and_Phones#Recognition_of_devices_under_Linux
7> Install the APK file in your phone via ADB or whatever other method you prefer:
../android-sdk-linux_x86/tools/adb install android/bin/TurboChessClock4Android-debug.apk
If the package is already installed you need need to do this instead:
../android-sdk-linux_x86/tools/adb uninstall com.pascal.turbochessclock ../android-sdk-linux_x86/tools/adb install android/bin/TurboChessClock4Android-debug.apk
Manifest configuration
Control the program restart
By default the program will restart on orientation change, on keyboard change, and in a lot of other cases. This is usually unwanted. To disable program restart o keyboard showing and orientation changed add this to the manifest file:
<activity
...
android:configChanges="orientation|keyboardHidden"
See also:
Resource files
Guidelines for the Icons
Read here: http://developer.android.com/guide/practices/ui_guidelines/icon_design.html
Using other APIs
Using the Timer
The Android API bindings include a handy timer control called TAndroidTimer. It works just like a Runnable, and inside it a Handler class is utilized to run the Runnable in the main GUI thread so that event executed in this timer can call Android APIs.
Timer example
<delphi> program turbochessclock4android;
{$mode objfpc}{$H+}
uses
Classes, SysUtils, androidpipescomm, androidview, javalang, androidapp, androidtimer;//, gles11;
type
TEventHandler = class public procedure HandleOnTimer(ASender: TObject); procedure buttonClickCallback(v: TView); end;
var
//... TimerCount: Integer = 0; MyTimer: TAndroidTimer; MyEventHandler: TEventHandler;
procedure TEventHandler.buttonClickCallback(v: TView); begin
MyTimer.postDelayed(100);
end;
procedure TEventHandler.HandleOnTimer(ASender: TObject); begin
Inc(TimerCount); tv.setText(Format('Timer event #%d', [TimerCount])); MyTimer.postDelayed(1000);
end;
begin
MyEventHandler := TEventHandler.Create; // ...
end. </delphi>