Hi all …
Today’s post is all about calling functions using Simple Strings.
Here we will do two things.
1. Call a function without parameters.
2. Call a function with parameters.
This is the class which contains the functions that we are going to call using “simple Strings”.
package com.coderzheaven.Stringtofunction;public class Test { public String functionWithParams(String p1, String p2) { return p1 + ", " + p2; } public String noParamsFunction() { return "Return from noParamsFunction"; }} |
Now this is the main activity that calls these functions.
package com.coderzheaven.Stringtofunction;import java.lang.reflect.Method;import android.app.Activity;import android.os.Bundle;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;public class MainActivity extends Activity { String TAG = getClass().getSimpleName(); TextView tv; @SuppressWarnings("rawtypes") @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); final Object paramsObj[] = { "Hello", "CoderzHeaven" }; final Class[] class_params = { String.class, String.class }; final String class_name = getPackageName() + ".Test"; Button b1 = (Button) findViewById(R.id.button1); b1.setOnClickListener(new OnClickListener() { public void onClick(View v) { /** This is the function without parameters in Test.java **/ callFunctionWithoutParameter(class_name, "noParamsFunction"); } }); Button b2 = (Button) findViewById(R.id.button2); b2.setOnClickListener(new OnClickListener() { public void onClick(View v) { /** This is the function with two parameters in Test.java **/ callFunctionWithParams(class_name, "functionWithParams", class_params, paramsObj); } }); tv = (TextView)findViewById(R.id.tv); } @SuppressWarnings({ "rawtypes", "unchecked" }) void callFunctionWithoutParameter(String class_name, String function_name) { try { Class c = Class.forName(class_name); Method m = c.getMethod(function_name); Object iClass = c.newInstance(); String p = (String) m.invoke(iClass); Log.i(TAG, p); tv.setText("Result (Without Prameters) : " + p); } catch (Exception e) { e.printStackTrace(); } } @SuppressWarnings({ "rawtypes", "unchecked" }) void callFunctionWithParams(String aClass, String aMethod, Class[] params, Object[] args) { try { Class c = Class.forName(aClass); Method m = c.getDeclaredMethod(aMethod, params); Object i = c.newInstance(); String p = (String) m.invoke(i, args); Log.i(TAG, p); tv.setText("Result (With Prameters) : " + p); } catch (Exception e) { e.printStackTrace(); } }} |
Now this is the layout that the mainactivity uses.
<LinearLayout 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:orientation="vertical" > <Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Call function without parameters" /> <Button android:id="@+id/button2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Call function with parameters" /> <TextView android:id="@+id/tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="@dimen/padding_medium" android:text="@string/hello_world" tools:context=".MainActivity" /></LinearLayout> |