How to develop a soft keyboard for Android? [closed]

Some tips:

• Read this tutorial: Creating an Input Method
• clone this repo: LatinIME

About your questions:

An inputMethod is basically an Android Service, so yes, you can do HTTP and all the stuff you can do in a Service.

You can open Activities and dialogs from the InputMethod. Once again, it's just a Service.

I've been developing an IME, so ask again if you run into an issue.

Create Custom Key Board for Own EditText

Download Entire Code

In this post i Created Simple Keyboard which contains Some special keys like ( France keys ) and it's supported Capital letters and small letters and Number keys and some Symbols .

package sra.keyboard;import android.app.Activity;import android.os.Bundle;import android.util.Log;import android.view.MotionEvent;import android.view.View;import android.view.WindowManager;import android.view.View.OnClickListener;import android.view.View.OnFocusChangeListener;import android.view.View.OnTouchListener;import android.widget.Button;import android.widget.EditText;import android.widget.RelativeLayout;public class Main extends Activity implements OnTouchListener, OnClickListener,  OnFocusChangeListener { private EditText mEt, mEt1; // Edit Text boxes private Button mBSpace, mBdone, mBack, mBChange, mNum; private RelativeLayout mLayout, mKLayout; private boolean isEdit = false, isEdit1 = false; private String mUpper = "upper", mLower = "lower"; private int w, mWindowWidth; private String sL[] = { "a", "b", "c", "d", "e", "f", "g", "h", "i", "j",   "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w",   "x", "y", "z", "ç", "à", "é", "è", "û", "î" }; private String cL[] = { "A", "B", "C", "D", "E", "F", "G", "H", "I", "J",   "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W",   "X", "Y", "Z", "ç", "à", "é", "è", "û", "î" }; private String nS[] = { "!", ")", "'", "#", "3", "$", "%", "&", "8", "*",   "?", "/", "+", "-", "9", "0", "1", "4", "@", "5", "7", "(", "2",   "\"", "6", "_", "=", "]", "[", "<", ">", "|" }; private Button mB[] = new Button[32]; @Override public void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  try {   setContentView(R.layout.main);   // adjusting key regarding window sizes   setKeys();   setFrow();   setSrow();   setTrow();   setForow();   mEt = (EditText) findViewById(R.id.xEt);   mEt.setOnTouchListener(this);   mEt.setOnFocusChangeListener(this);   mEt1 = (EditText) findViewById(R.id.et1);   mEt1.setOnTouchListener(this);   mEt1.setOnFocusChangeListener(this);   mEt.setOnClickListener(this);   mEt1.setOnClickListener(this);   mLayout = (RelativeLayout) findViewById(R.id.xK1);   mKLayout = (RelativeLayout) findViewById(R.id.xKeyBoard);  } catch (Exception e) {   Log.w(getClass().getName(), e.toString());  } } @Override public boolean onTouch(View v, MotionEvent event) {  if (v == mEt) {   hideDefaultKeyboard();   enableKeyboard();  }  if (v == mEt1) {   hideDefaultKeyboard();   enableKeyboard();  }  return true; } @Override public void onClick(View v) {  if (v == mBChange) {   if (mBChange.getTag().equals(mUpper)) {    changeSmallLetters();    changeSmallTags();   } else if (mBChange.getTag().equals(mLower)) {    changeCapitalLetters();    changeCapitalTags();   }  } else if (v != mBdone && v != mBack && v != mBChange && v != mNum) {   addText(v);  } else if (v == mBdone) {   disableKeyboard();  } else if (v == mBack) {   isBack(v);  } else if (v == mNum) {   String nTag = (String) mNum.getTag();   if (nTag.equals("num")) {    changeSyNuLetters();    changeSyNuTags();    mBChange.setVisibility(Button.INVISIBLE);   }   if (nTag.equals("ABC")) {    changeCapitalLetters();    changeCapitalTags();   }  } } @Override public void onFocusChange(View v, boolean hasFocus) {  if (v == mEt && hasFocus == true) {   isEdit = true;   isEdit1 = false;  } else if (v == mEt1 && hasFocus == true) {   isEdit = false;   isEdit1 = true;  } } private void addText(View v) {  if (isEdit == true) {   String b = "";   b = (String) v.getTag();   if (b != null) {    // adding text in Edittext    mEt.append(b);   }  }  if (isEdit1 == true) {   String b = "";   b = (String) v.getTag();   if (b != null) {    // adding text in Edittext    mEt1.append(b);   }  } } private void isBack(View v) {  if (isEdit == true) {   CharSequence cc = mEt.getText();   if (cc != null && cc.length() > 0) {    {     mEt.setText("");     mEt.append(cc.subSequence(0, cc.length() - 1));    }   }  }  if (isEdit1 == true) {   CharSequence cc = mEt1.getText();   if (cc != null && cc.length() > 0) {    {     mEt1.setText("");     mEt1.append(cc.subSequence(0, cc.length() - 1));    }   }  } } private void changeSmallLetters() {  mBChange.setVisibility(Button.VISIBLE);  for (int i = 0; i < sL.length; i++)   mB[i].setText(sL[i]);  mNum.setTag("12#"); } private void changeSmallTags() {  for (int i = 0; i < sL.length; i++)   mB[i].setTag(sL[i]);  mBChange.setTag("lower");  mNum.setTag("num"); } private void changeCapitalLetters() {  mBChange.setVisibility(Button.VISIBLE);  for (int i = 0; i < cL.length; i++)   mB[i].setText(cL[i]);  mBChange.setTag("upper");  mNum.setText("12#"); } private void changeCapitalTags() {  for (int i = 0; i < cL.length; i++)   mB[i].setTag(cL[i]);  mNum.setTag("num"); } private void changeSyNuLetters() {  for (int i = 0; i < nS.length; i++)   mB[i].setText(nS[i]);  mNum.setText("ABC"); } private void changeSyNuTags() {  for (int i = 0; i < nS.length; i++)   mB[i].setTag(nS[i]);  mNum.setTag("ABC"); } // enabling customized keyboard private void enableKeyboard() {  mLayout.setVisibility(RelativeLayout.VISIBLE);  mKLayout.setVisibility(RelativeLayout.VISIBLE); } // Disable customized keyboard private void disableKeyboard() {  mLayout.setVisibility(RelativeLayout.INVISIBLE);  mKLayout.setVisibility(RelativeLayout.INVISIBLE); } private void hideDefaultKeyboard() {  getWindow().setSoftInputMode(    WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN); } private void setFrow() {  w = (mWindowWidth / 13);  w = w - 15;  mB[16].setWidth(w);  mB[22].setWidth(w + 3);  mB[4].setWidth(w);  mB[17].setWidth(w);  mB[19].setWidth(w);  mB[24].setWidth(w);  mB[20].setWidth(w);  mB[8].setWidth(w);  mB[14].setWidth(w);  mB[15].setWidth(w);  mB[16].setHeight(50);  mB[22].setHeight(50);  mB[4].setHeight(50);  mB[17].setHeight(50);  mB[19].setHeight(50);  mB[24].setHeight(50);  mB[20].setHeight(50);  mB[8].setHeight(50);  mB[14].setHeight(50);  mB[15].setHeight(50); } private void setSrow() {  w = (mWindowWidth / 10);  mB[0].setWidth(w);  mB[18].setWidth(w);  mB[3].setWidth(w);  mB[5].setWidth(w);  mB[6].setWidth(w);  mB[7].setWidth(w);  mB[26].setWidth(w);  mB[9].setWidth(w);  mB[10].setWidth(w);  mB[11].setWidth(w);  mB[26].setWidth(w);  mB[0].setHeight(50);  mB[18].setHeight(50);  mB[3].setHeight(50);  mB[5].setHeight(50);  mB[6].setHeight(50);  mB[7].setHeight(50);  mB[9].setHeight(50);  mB[10].setHeight(50);  mB[11].setHeight(50);  mB[26].setHeight(50); } private void setTrow() {  w = (mWindowWidth / 12);  mB[25].setWidth(w);  mB[23].setWidth(w);  mB[2].setWidth(w);  mB[21].setWidth(w);  mB[1].setWidth(w);  mB[13].setWidth(w);  mB[12].setWidth(w);  mB[27].setWidth(w);  mB[28].setWidth(w);  mBack.setWidth(w);  mB[25].setHeight(50);  mB[23].setHeight(50);  mB[2].setHeight(50);  mB[21].setHeight(50);  mB[1].setHeight(50);  mB[13].setHeight(50);  mB[12].setHeight(50);  mB[27].setHeight(50);  mB[28].setHeight(50);  mBack.setHeight(50); } private void setForow() {  w = (mWindowWidth / 10);  mBSpace.setWidth(w * 4);  mBSpace.setHeight(50);  mB[29].setWidth(w);  mB[29].setHeight(50);  mB[30].setWidth(w);  mB[30].setHeight(50);  mB[31].setHeight(50);  mB[31].setWidth(w);  mBdone.setWidth(w + (w / 1));  mBdone.setHeight(50); } private void setKeys() {  mWindowWidth = getWindowManager().getDefaultDisplay().getWidth(); // getting  // window  // height  // getting ids from xml files  mB[0] = (Button) findViewById(R.id.xA);  mB[1] = (Button) findViewById(R.id.xB);  mB[2] = (Button) findViewById(R.id.xC);  mB[3] = (Button) findViewById(R.id.xD);  mB[4] = (Button) findViewById(R.id.xE);  mB[5] = (Button) findViewById(R.id.xF);  mB[6] = (Button) findViewById(R.id.xG);  mB[7] = (Button) findViewById(R.id.xH);  mB[8] = (Button) findViewById(R.id.xI);  mB[9] = (Button) findViewById(R.id.xJ);  mB[10] = (Button) findViewById(R.id.xK);  mB[11] = (Button) findViewById(R.id.xL);  mB[12] = (Button) findViewById(R.id.xM);  mB[13] = (Button) findViewById(R.id.xN);  mB[14] = (Button) findViewById(R.id.xO);  mB[15] = (Button) findViewById(R.id.xP);  mB[16] = (Button) findViewById(R.id.xQ);  mB[17] = (Button) findViewById(R.id.xR);  mB[18] = (Button) findViewById(R.id.xS);  mB[19] = (Button) findViewById(R.id.xT);  mB[20] = (Button) findViewById(R.id.xU);  mB[21] = (Button) findViewById(R.id.xV);  mB[22] = (Button) findViewById(R.id.xW);  mB[23] = (Button) findViewById(R.id.xX);  mB[24] = (Button) findViewById(R.id.xY);  mB[25] = (Button) findViewById(R.id.xZ);  mB[26] = (Button) findViewById(R.id.xS1);  mB[27] = (Button) findViewById(R.id.xS2);  mB[28] = (Button) findViewById(R.id.xS3);  mB[29] = (Button) findViewById(R.id.xS4);  mB[30] = (Button) findViewById(R.id.xS5);  mB[31] = (Button) findViewById(R.id.xS6);  mBSpace = (Button) findViewById(R.id.xSpace);  mBdone = (Button) findViewById(R.id.xDone);  mBChange = (Button) findViewById(R.id.xChange);  mBack = (Button) findViewById(R.id.xBack);  mNum = (Button) findViewById(R.id.xNum);  for (int i = 0; i < mB.length; i++)   mB[i].setOnClickListener(this);  mBSpace.setOnClickListener(this);  mBdone.setOnClickListener(this);  mBack.setOnClickListener(this);  mBChange.setOnClickListener(this);  mNum.setOnClickListener(this); }}

A good place to start is the sample application provided on the developer docs.

• Guidelines would be to just make it as usable as possible. Take a look at the others available on the market to see what you should be aiming for
• Yes, services can do most things, including internet; provided you have asked for those permissions
• You can open activities and do anything you like n those if you run into a problem with doing some things in the keyboard. For example HTC's keyboard has a button to open the settings activity, and another to open a dialog to change languages.

Take a look at other IME's to see what you should be aiming for. Some (like the official one) are open source.