Export data in android

The idea is simple:

1. Read the database data and process it as needed.

2. Write Data to the SD card

The following uses the export system contact as an example:

MainActivity:

Package com. home. exportcontact; import java. io. file; import java. io. fileWriter; import java. io. IOException; import android. app. activity; import android. app. alertDialog; import android. content. context; import android. content. dialogInterface; import android. database. cursor; import android. OS. bundle; import android. OS. environment; import android. OS. handler; import android. OS. message; import android. provider. contac TsContract; import android. provider. contactsContract. commonDataKinds. phone; import android. provider. contactsContract. commonDataKinds. structuredName; import android. provider. contactsContract. contacts. data; import android. view. view; import android. view. view. onClickListener; import android. widget. button; import android. widget. textView; public class MainActivity extends Activity implements OnClickListener {pr Ivate Button exportBtn; // export Button private TextView showText; // display progress text // export the location of the txt file private final static String OUTPUT_PATH = Environment. getExternalStorageDirectory () + "/my contacts .txt"; private static final int OUTPUT_FAIL = 0; // export Failure Identification private static final int OUTPUT_SUCCESS = 1; // export success identification private static int count; // export the Contact Count private Thread mOutputThread; // export the contact Thread // space private static final String SPACE_1 =" "; Private static final String SPACE_2 = SPACE_1 + SPACE_1; private static final String SPACE_4 = SPACE_2 + SPACE_2; private static final String SPACE_8 = SPACE_4 + SPACE_4; private static final String SPACE_11 = SPACE_8 + SPACE_2 + SPACE_1; @ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. main); exportBtn = (Button) findViewById (R. Id. main_btn_export); exportBtn. setOnClickListener (this); showText = (TextView) findViewById (R. id. main_ TV _show) ;}@ Overridepublic void onClick (View v) {if (v = exportBtn) {outputContact ();}} /*** export contact entry */private void outputContact () {File file = new File (OUTPUT_PATH); if (! File. exists () {startOutputContact ();} else {createDialog (this, "warning", "my contact .txt already exists, overwrite? ") ;}}/*** Create prompt dialog box ** @ param context * @ param title * @ param message */private void createDialog (Context context, String title, String message) {AlertDialog. builder builder = new AlertDialog. builder (context); builder. setTitle (title); builder. setMessage (message); builder. setPositiveButton ("OK", new DialogInterface. onClickListener () {public void onClick (DialogInterface dialog, int whichButton) {startOu TputContact () ;}}); builder. setNeutralButton ("cancel", new DialogInterface. onClickListener () {public void onClick (DialogInterface dialog, int whichButton) {dialog. cancel () ;}}); builder. show ();}/*** enable the export contact subthread */private void startOutputContact () {setOutputWidgetEnabled (false); showText. setText ("exporting contact... "); if (mOutputThread! = Null) {mOutputThread. interrupt (); mOutputThread = null;} mOutputThread = new Thread (new OutputRunnable (this); if (mOutputThread! = Null) {mOutputThread. start () ;}}/*** set the availability of the exported component */private void setOutputWidgetEnabled (boolean enabled) {exportBtn. setEnabled (enabled); if (! Enabled) {showText. setText ("") ;}} class OutputRunnable implements Runnable {private Context context; public OutputRunnable (Context context) {this. context = context ;}@ Overridepublic void run () {boolean result = doOutputContact (context); if (result) {handler. sendEmptyMessage (OUTPUT_SUCCESS);} else {handler. sendEmptyMessage (OUTPUT_FAIL) ;}}/ *** handle UI prompts */private Handler handler = new Handler () {public Void handleMessage (Message msg) {if (msg. what = OUTPUT_SUCCESS) {showText. setText (String. format ("% d contact records exported successfully", count); setOutputWidgetEnabled (true);} else if (msg. what = OUTPUT_FAIL) {showText. setText ("failed to import the contact"); setOutputWidgetEnabled (true );}}}; /*** export the contact from the database ** @ param context * @ return indicates whether the contact is successful */private boolean doOutputContact (Context context) {count = 0; try {String result = readFromConta CtDatabase (context); writeFile (OUTPUT_PATH, result);} catch (Exception e) {return false;} return true ;} /*** read contact information from the database ** @ param context * @ return information result */private String readFromContactDatabase (Context context) {StringBuilder resultBuilder = new StringBuilder (); cursor cursor = context. getContentResolver (). query (ContactsContract. data. CONTENT_URI, new String [] {StructuredName. DISPLAY_NAME, Data. RA W_CONTACT_ID}, Data. MIMETYPE + "=? ", New String [] {StructuredName. CONTENT_ITEM_TYPE}, null); while (cursor. moveToNext () {// obtain the name and the IDString displayName = cursor of each row. getString (0); int id = cursor. getInt (1); // get the Cursor mobileCursor = context of the phone number. getContentResolver (). query (ContactsContract. data. CONTENT_URI, new String [] {Phone. NUMBER}, Data. RAW_CONTACT_ID + "=" + id + "AND" + Data. DATA2 + "=" + 2, null, null); String mobileNum = ""; If (mobileCursor. moveToNext () {mobileNum = mobileCursor. getString (0);} mobileCursor. close (); // obtain the home phone number Cursor homeCursor = context. getContentResolver (). query (ContactsContract. data. CONTENT_URI, new String [] {Phone. NUMBER}, Data. RAW_CONTACT_ID + "=" + id + "AND" + Data. DATA2 + "=" + 1, null, null); String homeNum = ""; if (homeCursor. moveToNext () {homeNum = homeCursor. getString (0);} homeCursor. Close (); if (displayName! = Null &&! "". Equals (displayName) {String result = displayName + SPACE_4; if ("". equals (mobileNum) {result + = SPACE_11;} else {result + = mobileNum;} result + = SPACE_8 + homeNum + '\ n'; String checkString = resultBuilder. toString (); if (! CheckString. contains (result) & ("". equals (mobileNum) |! CheckString. contains (mobileNum) {resultBuilder. append (result); count ++ ;}} cursor. close (); return resultBuilder. toString ();}/*** write the contact information to SD ** @ param path * @ param info */private void writeFile (String path, String info) {try {File file = new File (path); FileWriter writer = new FileWriter (file, false); writer. write (info); writer. close ();} catch (IOException e) {e. printStackTrace ();}}}

Layout:

Permission: