Symmetry of letters
A letter appears, You can rotate or reflect it and an animation shows whether it is symmetrical in this way, plus a list of symmetries is built up.
app/res/drawable - pictures
An image of every letter, plus some buttons
app/res/values/strings.xml - strings
<![CDATA[
<resources>
<string name="app_name">Symmetry of letters</string>
<string name="descPic">Picture for animation</string>
<string name="rotateText">Rotate</string>
<string name="verticalText">Vertical</string>
<string name="horizontalText">Horizontal</string>
<string name="nextText">Next</string>
<string name="randomText">Random</string>
<string name="enterText">Enter</string>
<string name="query">"?"</string>
<string name="rotateMessage">"Rotational symmetry: "</string>
<string name="verticalMessage">"Reflective symmetry about a vertical axis: "</string>
<string name="horizontalMessage">"Rotational symmetry about a horizontal axis: "</string>
<string name="howTo">"Is this letter symmetrical? Click on buttons to find out."</string>
</resources>
]]>
app/res/layout/activity_main.xml - screen format
<![CDATA[
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MainActivity">
<TextView
android:id="@+id/howToLine"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:layout_centerHorizontal="true"
android:text="@string/howTo"
/>
<ImageView
android:id="@+id/pic"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:layout_width="500dp"
android:layout_height="250dp"
android:contentDescription="@string/descPic"
android:layout_centerHorizontal="true"
android:layout_below="@id/howToLine"
/>
<ImageView
android:id="@+id/verticalButton"
android:src="@drawable/vertical"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:layout_width="100dp"
android:layout_height="100dp"
android:contentDescription="@string/verticalText"
android:onClick="doVertical"
android:layout_below="@id/pic"
android:layout_centerHorizontal="true"
/>
<ImageView
android:id="@+id/rotateButton"
android:src="@drawable/rotate"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:layout_width="100dp"
android:layout_height="100dp"
android:contentDescription="@string/rotateText"
android:onClick="doRotate"
android:layout_below="@id/pic"
android:layout_toLeftOf="@id/verticalButton"
android:layout_toStartOf="@id/verticalButton"
/>
<ImageView
android:id="@+id/horizontalButton"
android:src="@drawable/horizontal"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:layout_width="100dp"
android:layout_height="100dp"
android:contentDescription="@string/horizontalText"
android:onClick="doHorizontal"
android:layout_below="@id/pic"
android:layout_toRightOf="@id/verticalButton"
android:layout_toEndOf="@id/verticalButton"
/>
<TextView
android:id="@+id/rotateLine"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingTop="@dimen/activity_vertical_margin"
android:text="@string/rotateMessage"
android:layout_below="@id/rotateButton"
/>
<TextView
android:id="@+id/rotateContent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingTop="@dimen/activity_vertical_margin"
android:layout_below="@id/rotateButton"
android:layout_toRightOf="@id/rotateLine"
android:layout_toEndOf="@id/rotateLine"
/>
<TextView
android:id="@+id/verticalLine"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/verticalMessage"
android:layout_below="@id/rotateLine"
/>
<TextView
android:id="@+id/verticalContent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/rotateLine"
android:layout_toRightOf="@id/verticalLine"
android:layout_toEndOf="@id/verticalLine"
/>
<TextView
android:id="@+id/horizontalLine"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/horizontalMessage"
android:paddingBottom="@dimen/activity_vertical_margin"
android:layout_below="@id/verticalLine"
/>
<TextView
android:id="@+id/horizontalContent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/verticalLine"
android:layout_toRightOf="@id/horizontalLine"
android:layout_toEndOf="@id/horizontalLine"
/>
<Button
android:id="@+id/nextButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/nextText"
android:onClick="doNext"
android:layout_below="@id/horizontalLine"
/>
<Button
android:id="@+id/randomButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/randomText"
android:onClick="doRandom"
android:layout_below="@id/horizontalLine"
android:layout_toRightOf="@id/nextButton"
android:layout_toEndOf="@id/nextButton"
/>
</RelativeLayout>
]]>
app/res/values/rotate.xml - animation for demonstrating OK rotate - rotate, then a light enlarge and reduce
<![CDATA[
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<rotate
android:fromDegrees="0"
android:toDegrees="180"
android:pivotX="50%"
android:pivotY="50%"
android:duration="1000" />
<scale
android:startOffset="1500"
android:fromXScale="1.0"
android:toXScale="1.1"
android:fromYScale="1.0"
android:toYScale="1.1"
android:pivotX="50%"
android:pivotY="50%"
android:duration="250" />
<scale
android:startOffset="1750"
android:fromXScale="1.0"
android:toXScale=".9"
android:fromYScale="1.0"
android:toYScale=".9"
android:pivotX="50%"
android:pivotY="50%"
android:duration="250" />
</set>
]]>
app/res/values/rotatex.xml - animation for demonstrating not OK rotate - rotate, then disappear into distance (throw away!)
<![CDATA[
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<rotate
android:fromDegrees="0"
android:toDegrees="180"
android:pivotX="50%"
android:pivotY="50%"
android:duration="1000" />
<scale
android:startOffset="2000"
android:fromXScale="1.0"
android:toXScale="0.0"
android:fromYScale="1.0"
android:toYScale="0.0"
android:pivotX="50%"
android:pivotY="50%"
android:duration="1000" />
</set>
]]>
app/res/values/vertical.xml - animation for demonstrating OK reflect about a vertical axis - reflect, then a light enlarge and reduce
<![CDATA[
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<scale
android:fromXScale="1.0"
android:toXScale="-1.0"
android:fromYScale="1.0"
android:toYScale="1.0"
android:pivotX="50%"
android:pivotY="50%"
android:duration="1000" />
<scale
android:startOffset="1500"
android:fromXScale="1.0"
android:toXScale="1.1"
android:fromYScale="1.0"
android:toYScale="1.1"
android:pivotX="50%"
android:pivotY="50%"
android:duration="250" />
<scale
android:startOffset="1750"
android:fromXScale="1.0"
android:toXScale=".9"
android:fromYScale="1.0"
android:toYScale=".9"
android:pivotX="50%"
android:pivotY="50%"
android:duration="250" />
</set>
]]>
app/res/values/verticallx.xml - animation for demonstrating not OK reflect about a vertical axis - reflect, then disappear into distance (throw away!)
<![CDATA[
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<scale
android:fromXScale="1.0"
android:toXScale="-1.0"
android:fromYScale="1.0"
android:toYScale="1.0"
android:pivotX="50%"
android:pivotY="50%"
android:duration="1000" />
<scale
android:startOffset="2000"
android:fromXScale="1.0"
android:toXScale="0.0"
android:fromYScale="1.0"
android:toYScale="0.0"
android:pivotX="50%"
android:pivotY="50%"
android:duration="1000" />
</set>
]]>
app/res/values/horizontal.xml - animation for demonstrating OK reflect about a horizontal axis - reflect, then a light enlarge and reduce
<![CDATA[
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<scale
android:fromXScale="1.0"
android:toXScale="1.0"
android:fromYScale="1.0"
android:toYScale="-1.0"
android:pivotX="50%"
android:pivotY="50%"
android:duration="1000" />
<scale
android:startOffset="1500"
android:fromXScale="1.0"
android:toXScale="1.1"
android:fromYScale="1.0"
android:toYScale="1.1"
android:pivotX="50%"
android:pivotY="50%"
android:duration="250" />
<scale
android:startOffset="1750"
android:fromXScale="1.0"
android:toXScale=".9"
android:fromYScale="1.0"
android:toYScale=".9"
android:pivotX="50%"
android:pivotY="50%"
android:duration="250" />
</set>
]]>
app/res/values/horizontalx.xml - animation for demonstrating not OK reflect about a horizontal axis - reflect, then disappear into distance (throw away!)
<![CDATA[
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<scale
android:fromXScale="1.0"
android:toXScale="1.0"
android:fromYScale="1.0"
android:toYScale="-1.0"
android:pivotX="50%"
android:pivotY="50%"
android:duration="1000" />
<scale
android:startOffset="2000"
android:fromXScale="1.0"
android:toXScale="0.0"
android:fromYScale="1.0"
android:toYScale="0.0"
android:pivotX="50%"
android:pivotY="50%"
android:duration="1000" />
</set>
]]>
app/java/com.(the project name)/MainActivity - main code for app
<![CDATA[
package com.edkins.symmetryofletters;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
public static int current = 0;
public static int ok = 1;
static Random myRand = new Random();
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ok = 1; current = 0;
doNew();
}
public void doRotate(View view) {
if (ok==0) {return;}
ImageView pic = (ImageView) findViewById(R.id.pic);
if (rotate[current] == 1) {
Animation anim = AnimationUtils.loadAnimation(this, R.anim.rotate);
anim.setAnimationListener(new Animation.AnimationListener() {
public void onAnimationStart(Animation animation) {ok=0;}
public void onAnimationRepeat(Animation animation) {}
public void onAnimationEnd(Animation animation) {
ok=1;
TextView line = (TextView) findViewById(R.id.rotateContent);
line.setText("Yes");
}
});
pic.startAnimation(anim);
}
else {
Animation anim = AnimationUtils.loadAnimation(this, R.anim.rotatex);
anim.setAnimationListener(new Animation.AnimationListener() {
public void onAnimationStart(Animation animation) {ok=0;}
public void onAnimationRepeat(Animation animation) {}
public void onAnimationEnd(Animation animation) {
ok=1;
TextView line = (TextView) findViewById(R.id.rotateContent);
line.setText("No");
}
});
pic.startAnimation(anim);
}
}
public void doVertical(View view) {
if (ok==0) {return;}
ImageView pic = (ImageView) findViewById(R.id.pic);
if (vertical[current] == 1) {
Animation anim = AnimationUtils.loadAnimation(this, R.anim.vertical);
anim.setAnimationListener(new Animation.AnimationListener() {
public void onAnimationStart(Animation animation) {ok=0;}
public void onAnimationRepeat(Animation animation) {}
public void onAnimationEnd(Animation animation) {
ok=1;
TextView line = (TextView) findViewById(R.id.verticalContent);
line.setText("Yes");}
});
pic.startAnimation(anim);
}
else {
Animation anim = AnimationUtils.loadAnimation(this, R.anim.verticalx);
anim.setAnimationListener(new Animation.AnimationListener() {
public void onAnimationStart(Animation animation) {ok=0;}
public void onAnimationRepeat(Animation animation) {}
public void onAnimationEnd(Animation animation) {
ok=1;
TextView line = (TextView) findViewById(R.id.verticalContent);
line.setText("No");
}
});
pic.startAnimation(anim);
}
}
public void doHorizontal(View view) {
if (ok==0) {return;}
ImageView pic = (ImageView) findViewById(R.id.pic);
if (horizontal[current] == 1) {
Animation anim = AnimationUtils.loadAnimation(this, R.anim.horizontal);
anim.setAnimationListener(new Animation.AnimationListener() {
public void onAnimationStart(Animation animation) {ok=0;}
public void onAnimationRepeat(Animation animation) {}
public void onAnimationEnd(Animation animation) {
ok=1;
TextView line = (TextView) findViewById(R.id.horizontalContent);
line.setText("Yes");
}
});
pic.startAnimation(anim);
}
else {
Animation anim = AnimationUtils.loadAnimation(this, R.anim.horizontalx);
anim.setAnimationListener(new Animation.AnimationListener() {
public void onAnimationStart(Animation animation) {ok=0;}
public void onAnimationRepeat(Animation animation) {}
public void onAnimationEnd(Animation animation) {
ok=1;
TextView line = (TextView) findViewById(R.id.horizontalContent);
line.setText("No");
}
});
pic.startAnimation(anim);
}
}
public void doNew() {
if (ok==0) {return;}
ImageView pic = (ImageView) findViewById(R.id.pic);
pic.setImageResource(start[current]);
TextView line1 = (TextView) findViewById(R.id.rotateContent);
line1.setText("?");
TextView line2 = (TextView) findViewById(R.id.verticalContent);
line2.setText("?");
TextView line3 = (TextView) findViewById(R.id.horizontalContent);
line3.setText("?");
}
public void doNext(View view) {
if (ok==0) {return;}
current++;
if (current>25) {current = 0;}
doNew();
}
public void doRandom(View view) {
if (ok==0) {return;}
int old = current;
while (old==current) {current = myRand.nextInt(26);}
doNew();
}
public static int [] start = {
R.drawable.a, R.drawable.b, R.drawable.c, R.drawable.d, R.drawable.e,
R.drawable.f, R.drawable.g, R.drawable.h, R.drawable.i, R.drawable.j,
R.drawable.k, R.drawable.l, R.drawable.m, R.drawable.n, R.drawable.o,
R.drawable.p, R.drawable.q, R.drawable.r, R.drawable.s, R.drawable.t,
R.drawable.u, R.drawable.v, R.drawable.w, R.drawable.x, R.drawable.y,
R.drawable.z,
};
public static int [] rotate = {
0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1
};
public static int [] vertical = {
1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0
};
public static int [] horizontal = {
0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0
};
}
]]>
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© Jo Edkins 2016