I have created a Custom View component and my layout file consists of a button and the CustomView.Whenever I press the button,I want to update the Filename in the CustomView class.This occurs by invoking the set_file method of the customview and the set_file method is called in the function perform();.However I get an error while doing so.
HERE are my 3 classes.
TestActivity.java
package com.android.pack;
import java.net.URISyntaxException;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.Toast;
public class TestActivity extends Activity {
/** Called when the activity is first created. */
int height;
int weight;
Button select;
customview cView;
String path="";
String pathchk="";
String temp="";
private static final int FILE_SELECT_CODE = 0;
public void perform()
{
cView.set_file(pathchk);
cView.postInvalidate();
}
public void showFileChooser(View v) {
Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
intent.setType("*/*");
intent.addCategory(Intent.CATEGORY_OPENABLE);
try {
startActivityForResult(
Intent.createChooser(intent, "Select a File to Upload"),
FILE_SELECT_CODE);
} catch (android.content.ActivityNotFoundException ex) {
// Potentially direct the user to the Market with a Dialog
Toast.makeText(this, "Please install a File Manager.",
Toast.LENGTH_SHORT).show();
}
}
protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
switch (requestCode) {
case FILE_SELECT_CODE:
if (resultCode == RESULT_OK) {
// Get the Uri of the selected file
Uri uri = data.getData();
Log.v("check", "File Uri: " + uri.toString());
// Get the path
try {
path = FileUtils.getPath(this, uri);
pathchk=path.substring(12);
perform();
} catch (URISyntaxException e) {
// TODO Auto-generated catch block
Log.v("error", "File Path: "+pathchk);
}
Log.v("check", "File Path: "+path);
// Get the file instance
// File file = new File(path);
// Initiate the upload
}
break;
}
super.onActivityResult(requestCode, resultCode, data);
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LayoutInflater li = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View v=li.inflate(R.layout.main, null);
cView = (customview)findViewById(R.id.customview1);
LinearLayout ll = new LinearLayout(this);
ll.setOrientation(LinearLayout.VERTICAL);
select=(Button)findViewById(R.id.button1);
// select.setText("Select a File");
/* select.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
showFileChooser();
Toast.makeText(getApplicationContext(), "The File "+path+" is loaded",Toast.LENGTH_LONG); }
}); */
// LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
// LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
//ll.addView(select, new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
//ll.addView(cView, layoutParams);
setContentView(R.layout.main);
}
}
customview.java
package com.android.pack;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.StringTokenizer;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.gesture.Gesture;
import android.gesture.GesturePoint;
import android.gesture.GestureStroke;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
import android.os.Environment;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.view.View.*
;
import android.widget.Button;
import android.widget.Toast;
public class customview extends View implements OnClickListener
{
ArrayList<GesturePoint> child;
ArrayList<Point> pnts;
Point pnt=new Point();
File myFile;
BufferedReader br;
FileInputStream in;
InputStreamReader fin;
GestureStroke gest;
Gesture my_final=new Gesture();
String Token;
long Time=30000000;
int flag=0;
boolean line=true;
boolean points=true;
Button b1;
int height;
int weight;
String Filename="";
ArrayList<Path> paths;
Path mypath;
Paint mypaint=new Paint();//
public void set_file(String a)// to set the File
{
Filename=a;
//clear_screen();
}
public customview(Context context)
{
super(context);
this.setOnClickListener(this);
mypaint.setColor(Color.RED);
mypaint.setAntiAlias(true);
mypaint.setStyle(Paint.Style.STROKE);
mypaint.setStrokeWidth(5);
myFile=Environment.getExternalStorageDirectory();
}
public customview(Context context,AttributeSet att)
{
super(context,att);
this.setOnClickListener(this);
mypaint.setColor(Color.RED);
mypaint.setAntiAlias(true);
mypaint.setStyle(Paint.Style.STROKE);
mypaint.setStrokeWidth(5);
myFile=Environment.getExternalStorageDirectory();
}
public void make_shape()
{
paths=new ArrayList<Path>();
pnts=new ArrayList<Point>();
height=this.getHeight();
weight=this.getWidth();
Log.v("Main_custom_height",height+"");
Log.v("Main_custom_weight",weight+"");
try
{
File file = new File(myFile,Filename);
br=new BufferedReader(new FileReader(file));
String read;
while((read=br.readLine())!=null)
{
//Toast.makeText(Create_pathActivity.this,read,Toast.LENGTH_SHORT).show();
if(read.equals(".PEN_UP"))
{
flag=0;
gest=new GestureStroke(child);
mypath=gest.getPath();
paths.add(mypath);
my_final.addStroke(gest);
}
if(flag==1)
{
StringTokenizer st = new StringTokenizer(read);
for(int i=0;i<=2;i++)
{
if(i==0)
{
Token=st.nextToken();
pnt.x=Integer.parseInt(Token);
//pnt.x=pnt.x+200;
//pnt.x=pnt.x/5;
Log.v("PointX",Token);
}
if(i==1)
{
Token=st.nextToken();
pnt.y=Integer.parseInt(Token);
//pnt.y=pnt.y+165;
//pnt.y=pnt.y/5;
Log.v("PointY",Token);
}
if(i==2)
{
Time=Time+10;
GesturePoint temp=new GesturePoint(pnt.x,pnt.y,Time);
child.add(temp);
}
}
Point p=new Point();
p.x=pnt.x;
p.y=pnt.y;
pnts.add(p);
}
if(read.equals(".PEN_DOWN"))
{
flag=1;
child=new ArrayList<GesturePoint>();
}
}
}catch (Exception e)
{
}
}
protected void onDraw(Canvas canvas)
{
if(points==true && line==false)
{
for (Point point : pnts) {
canvas.drawCircle(point.x, point.y, 3,mypaint);
}
}
if(points==false && line==true)
{
for( int i=0;i<paths.size();i++)
{
canvas.drawPath(paths.get(i), mypaint);
}
}
}
public void scale()
{
int S_width = 320, S_height = 410, width, height, DiffW, DiffH;
int max_x = 0, max_y = 0, min_x = 320, min_y = 410;
int new_x, new_y;
int i;
float scale;
for(i=0; i<pnts.size(); i++)
{
if( pnts.get(i).x > max_x )
max_x = pnts.get(i).x;
if( pnts.get(i).x < min_x )
min_x = pnts.get(i).x;
if( pnts.get(i).y > max_y )
max_y = pnts.get(i).y;
if( pnts.get(i).y < min_y )
min_y = pnts.get(i).y;
}
width = max_x - min_x;
height = max_y - min_y;
DiffW = Math.abs(S_width - width);
DiffH = Math.abs(S_height - height);
if( DiffW > DiffH )
scale = width/300;
else
scale = height/390;
//scaling
for(i=0; i<pnts.size(); i++)
{
pnts.get(i).x /= scale;
pnts.get(i).y /= scale;
}
new_x = max_x - 10;
new_y = min_y - 10;
//top-left shifting
for(i=0; i<pnts.size(); i++)
{
pnts.get(i).x -= new_x;
pnts.get(i).y -= new_y;
}
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if(Filename.equals(""))
{
Toast.makeText(getContext(),"Select a file ist", Toast.LENGTH_SHORT);
return;
}
make_shape();
AlertDialog.Builder builder = new AlertDialog.Builder(getContext());
builder.setCancelable(true);
builder.setTitle("Draw a line or a path");
builder.setInverseBackgroundForced(true);
builder.setPositiveButton("Line", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
line=true;
points=false;
invalidate();
}
});
builder.setNegativeButton("Point", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
line=false;
points=true;
//scale();
invalidate();
}
});
AlertDialog alert = builder.create();
alert.show();
}
}
**FileUtils.java**
package com.android.pack;
import java.net.URISyntaxException;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
public class FileUtils {
public static String getPath(Context context, Uri uri) throws URISyntaxException {
if ("content".equalsIgnoreCase(uri.getScheme())) {
String[] projection = { "_data" };
Cursor cursor = null;
try {
cursor = context.getContentResolver().query(uri, projection, null, null, null);
int column_index = cursor
.getColumnIndexOrThrow("_data");
if (cursor.moveToFirst()) {
return cursor.getString(column_index);
}
} catch (Exception e) {
// Eat it
}
}
else if ("file".equalsIgnoreCase(uri.getScheme())) {
return uri.getPath();
}
return null;
}
}
and here is my main.xml file
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<com.android.pack.customview
android:id="@+id/customview1"
android:layout_width="wrap_content"
android:layout_height="419dp"
android:layout_weight="0.63"
/>
<Button
android:id="@+id/button1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="select a file"
android:onClick="showFileChooser"/>
</LinearLayout>
My log cat is
01-09 12:04:42.038: D/szipinf(4990): Initializing inflate state
01-09 12:04:42.248: D/dalvikvm(4990): GC_CONCURRENT freed 281K, 50% free 2860K/5639K, external 0K/0K, paused 4ms+8ms
01-09 12:04:48.668: V/check(4990): File Uri: content://org.openintents.cmfilemanager/mimetype//mnt/sdcard/points.txt
01-09 12:04:48.698: D/AndroidRuntime(4990): Shutting down VM
01-09 12:04:48.698: W/dalvikvm(4990): threadid=1: thread exiting with uncaught exception (group=0x40018560)
01-09 12:04:48.698: E/AndroidRuntime(4990): FATAL EXCEPTION: main
01-09 12:04:48.698: E/AndroidRuntime(4990): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=0, result=-1, data=Intent { act=android.intent.action.VIEW dat=content://org.openintents.cmfilemanager/mimetype//mnt/sdcard/points.txt }} to activity {com.android.pack/com.android.pack.TestActivity}: java.lang.NullPointerException
01-09 12:04:48.698: E/AndroidRuntime(4990): at android.app.ActivityThread.deliverResults(ActivityThread.java:2653)
01-09 12:04:48.698: E/AndroidRuntime(4990): at android.app.ActivityThread.handleSendResult(ActivityThread.java:2695)
01-09 12:04:48.698: E/AndroidRuntime(4990): at android.app.ActivityThread.access$2000(ActivityThread.java:123)
01-09 12:04:48.698: E/AndroidRuntime(4990): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:969)
01-09 12:04:48.698: E/AndroidRuntime(4990): at android.os.Handler.dispatchMessage(Handler.java:99)
01-09 12:04:48.698: E/AndroidRuntime(4990): at android.os.Looper.loop(Looper.java:130)
01-09 12:04:48.698: E/AndroidRuntime(4990): at android.app.ActivityThread.main(ActivityThread.java:3835)
01-09 12:04:48.698: E/AndroidRuntime(4990): at java.lang.reflect.Method.invokeNative(Native Method)
01-09 12:04:48.698: E/AndroidRuntime(4990): at java.lang.reflect.Method.invoke(Method.java:507)
01-09 12:04:48.698: E/AndroidRuntime(4990): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:847)
01-09 12:04:48.698: E/AndroidRuntime(4990): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605)
01-09 12:04:48.698: E/AndroidRuntime(4990): at dalvik.system.NativeStart.main(Native Method)
01-09 12:04:48.698: E/AndroidRuntime(4990): Caused by: java.lang.NullPointerException
01-09 12:04:48.698: E/AndroidRuntime(4990): at com.android.pack.TestActivity.perform(TestActivity.java:32)
01-09 12:04:48.698: E/AndroidRuntime(4990): at com.android.pack.TestActivity.onActivityResult(TestActivity.java:64)
01-09 12:04:48.698: E/AndroidRuntime(4990): at android.app.Activity.dispatchActivityResult(Activity.java:3908)
01-09 12:04:48.698: E/AndroidRuntime(4990): at android.app.ActivityThread.deliverResults(ActivityThread.java:2649)
01-09 12:04:48.698: E/AndroidRuntime(4990): ... 11 more
Appreciate any help!!
You have not done SetcontentView to call findviewby id. You will have to call